Just to clarify, all Deco X60s are connected wirelessly except the main X60 which has Ethernet of course. And unlike some households, the house is built ground up with concrete. No wooden walls here. 

And so to the update. So, I did more digging, I tested it out more. The issues still persist. Same disconnections, same network problems. It's an utter nightmare. Once again the previous Deco M5 did not have this issue. 

But here is the INTERESTING bit. 

The Main Deco router and the router provided by the ISP. 

Both of these have none of the said problems. No disconnects, No latency issues. Everything was going smooth. Do note that the speed of these are around 500mbps. They are located at the first floor. Upon testing and isolating this variable, I found that when you are nearer to the source. The Internet. Which in this case is at the first floor with the main deco unit. You get none of these disconnections and latency issues. The latency i'm talking about is not the one going to the server, because frankly it's all good until it just disconnects on you. This rules out the possibility that the ISP is at fault and that the main Deco Router is in anyway faulty. 

It is at this point that I am puzzled once again. It seems like the X60 is having a hard time doing what the M5 did so well. That is deliver the internet connection consistently with stable speed and connection. So far, I've done the usual reboot and I've since rearranged them, but no improvement no matter the placement. Once again if you are a new reader, the problem here isn't the devices losing connection to the wifi. It's suddenly disconnecting from any internet related service, application, etc. Example: Video Calls suddenly losing connection and coming back after half a minute. Games like Valorant having Network Connection Issues then suddenly being fine after a few seconds. 

Now, some of you may think that a simple Ethernet backhaul would fix this. I personally think so as well, but in my scenario, it is simply not possible to do this method. If it was, I would have done it ages ago believe me. So for the time being, we are stuck with a full wireless system. 

To clarify on how I concluded that the main deco and the ISP router are not in any fault. I tested the theory with applications, games, video conferences and more. Which I have yet to do to the Satellite unit of the 2nd floor which the 3rd floor Deco X60 is connected to. All these results came back excellently with no problems. It was smooth as silk. Now I will doing some further testing to the 2nd floor Deco unit which will give me a clear answer afterwards. 

Possible theories: 
1. There could be an issue with the 2nd Floor Deco X60 unit which may have hampered Internet delivery to the third floor -- Very unlikely, but still possible. 

2. This could be a Software issue with Deco itself. -- Possible. 
3. The 3rd Floor Deco X60 could have a fault. -- Possible. 

Either way, I do not see a clear cut solution or an easy fix to this problem. It has aggrevated my daily tasks and frankly, I'm so close to throwing a fit of rage and simply sacking all the decos hahahahaha. Kidding of course, these Deco's don't come cheap hahahahahaa. 

@TP-Link 

Oh I was just putting an update. 

Well to answer your questions. 
 

1. Would all the mobile devices lose connection spontaneously?

This was not observed. Spontaneously, I am unsure. But one thing has been confirmed by all users in the house. They get disconnected randomly in video calls, games and the like. I posted an update about this ,but i just saw your reply. Thank you btw for the reply. The disconnections are primarily observed at the farthest Deco X60 unit which is at the 3rd Level. The primary devices that lose connection are desktop, laptop devices. These are primarily in video conferences, Games, and the like. I yet have to test the 2nd floor deco unit if it suffers from the same problems. Will be doing that soon and will get back to you with the findings. 
 

2. How often would the connection drop out within one day?

Frankly, it happens once or twice every game. If you consider consider gaming for hours on end. Then easily once or twice every 40 minutes. Once every hour or two in calls. Do note: We do not lose the wifi connection. We are still connected to the wifi. But we lose internet connection for a limited amount of time. Seconds. Because it all comes back after less than a minute. Every indication in all devices say we are still connected to the internet and the Mesh Wifi. 
 

3. May I know who is your internet service provider and what is the model number of your main router?

 And as for the 20 devices, what are these devices?

The ISP is a Philippine based ISP. Yes, I am not from America unfortunately. But the TP-Link in my country does not have a forum as such. As for the IPS It's PLDT, Philippine Long Distance Telephone. It's relatively unknown to non-locals, but it is the biggest and most used ISP in the country. They provide us with constant and stable fiber internet at 500 mbps average for 2 years now and counting. 

The main router I do not know the name to. But from memory from the installer and from my testing. It is a Wifi router that connects directly to the Fiber Optic Cable. 2.4ghz and 5ghz frequency are both supported and working. It is a Gigabit capable router with 4 Ethernet ports, one used for the Deco main unit.  No devices are connected to this network as we utilize the Mesh Network. I will however get back to you as soon as I uncover the model number and such. 

As for devices these primarily consist of Samsung phones that are all less than 3 years old. Galaxy S20s, S10, A series phones. A few Ipads. and the important computers. These computers are all equipped with Tp-Link's AX3000 wifi card. All computers are recently built with the latest hardware. Ryzen 3000, B450 motherboards, RTX graphics, a boat load of ram. All running Windows 10 and 11. All updated to the latest builds. 

Thank you btw for replying. It means alot and I hope you have a nice day. I did post an update with more indepth detail, I hope that brings more light towards some of your questions. Once again thank you and have a nice day! 

Short but important update. 

I swapped the 2nd floor Deco X60 unit with the 3rd floor Deco X60 unit. Basically switching their position. 

No Change. Same disconnections and problems. 

So here is what I did: 

I used my old Deco M5 Router as a replacement for the farthest unit at the 3rd floor. 

Once again my situation goes something like this. 

1st Floor: Deco X60 [ Main Unit, Connected to Modem] 
2nd Floor: Deco X60  [ Wirelessly Connected] 
3rd Floor: Deco X60 [ Wirelessly Connected] 

This has brought sudden and random disconnections in games, calls, and more. Speeds however were great. All disconnections got reconnected in less than a minute. Swapping the Deco X60 units around didn't do anything. This was purely observed at the farthest unit, the third floor unit. The 1st and 2nd floor had no issue what-so-ever. 

Which confirms 2 things:

The Deco X60 itself is not at fault. The Software of the Deco X60 is potentially the faulty one. My theory is this probably has something to do with the OFDMA technology with the X60. 

Do note:

A Wired Ethernet Backhaul would have fixed this through-out all the deco X60 units, but I did not have this luxury in my options. I was fully stuck to a wireless setup. 

Not to mention, your internet source should be at the center of your house. Example: 

1st Floor: Satellite Deco X60 
2nd Floor : [Source of Internet, Deco X60 Main Unit]

3rd Floor: Satellite Deco X60 

This would have not brought up the issue of sudden disconnections.

IMPORTANT:
Once again to those who are new, this solution is for when your internet is fine through-out the entire wifi mesh system except when connecting to one of the satellite units. This usually shows itself as a random disconnects from services like games, video calls, chats, and the like. But all of this gets reconnected in less than a minute. 

 

Solution: 

1st Floor: Deco X60 
2nd Floor: Deco X60 
3rd Floor: Deco M5
 

Yes, I changed the 3rd floor deco X60 to my older Deco M5. This solved the disconnection problems. I know it doesn't make sense. But for some God knows what reason, it works. The disconnections are gone. I no longer get randomly disconnected. Like I said this is probably from the OFDMA technology of the X60. I do not know. All I know for sure is, the Deco X60 still has some optimization and software updates ahead of it in order to finally one day fix how it sends and receives the data efficiently and effectively. 

There are however some drawbacks to integrating my M5 back into the mix. I get lower overall speeds at the 3rd floor. 100mbps average compared to 160mbps average from the X60. But it no longer disconnects randomly and that is the important part. 

To any TP-Link Personnel, please look into the OFDMA technology of the X60. I believe this is the culprit of my problem. Most of all in a Suboptimal setup such as mine. 

I hope this helped to anyone who has the same problem as I do. Happy Gaming, God speed, and as of today... Merry Christmas! 
Best Regards to all! 
McClean7. 

@McClean7 

I am going through the same issue with my X60. In my case all are in the same floor and the entire house is about 1300 SQFT with concrete walls. 

Frequent disconnections from clients as well as other decos. I tried powerline ethernet between my main deco and 2nd satellite deco, which didn't help at all. I am stuck without options to try

@kgangaatharan 

So sorry you're in a similar dillema as I am hahahahaha. 

I recently fixed mine actually. I knew any software update and technical support would take too long, So I connected an Ethernet cable from the 2nd and 3rd floor. This fixed my issue completely and I no longer experience disconnections from the internet. 

As for you my friend, I see no logical explanation on why 1300 SQFT is already such a problem for the X60. In theory even a single X60 would be fine as it's rated for 2500SQFT each. Personally my setup covers an entire floor area of around 5000 SQFT. There could be many reasons and it's possible that your case might be the deco units being too close to one another. 1300SQFT is not a lot of room unless if it's 1300 Square meters, now that would be quite large. Though I cant confirm if this is your case, I haven't seen the layout and what. 

But I do recommend trying Wired Ethernet Backhaul. Connect a CAT6 cable [CAT 6, 6A, 6E and above should be fine] between the deco's in question. Let's see if that works. And if that isn't possible, do try monitoring which Deco unit you get disconnected mostly from. In my case it was the farthest unit. 

@McClean7 

Same problem here. 

Using M5 for more than 3 years. Decided to upgrade to x60 for the wifi6 benefits. 

Converge ISP. Recently upgraded to their 800mbps plan. No problem with the m5s. 

Upgraded to the x60s 3 pack a week ago. Same problem as yours. Wifi isnt disconnected but shows no internet connection. Tried playing the decos around. Changing the main decos. Even deleted the network couple of times. Changed ssids and all. No solution. 

Unfortunately, we are not in the US where we can return the items purchased :(

Cant hardwire the decos as well. 

Seriously contemplating on just putting the m5s back. 

@tp-link