Archer AX55 - some IoT devices disconnecting at random
Question first, then the background:
QUESTION: Why are some of my IoT devices randomly showing as disconnected to my TP-Link Archer AX55? Is the number of overall clients connected causing this issue, even though they're split between my main network and a separate IoT network and if so, do I need to pick up a new router to fix this?
BACKGROUND: At any given time, I can have between 25 and 32 devices total connected at the same time, when I consider family smartphones, laptops, an xbox, tablets a few Fire TV sticks, 11 IoT devices like thermostats, Wyze cams, home appliances, and then including 3 wired devices (1 TV, 1 other Fire TV, 1 Synology NAS).
I'm noticing consistently 1 or 2 of my IoT devices are randomly not connected to the internet when I access them through their respective apps. Even though the Tether app will show them as connected. IoT devices include a dishwasher, washing machine, dryer, and then 8 Wyze cams and 8 thermostats. It will be totally random but it's almost always two of the thermostats (funny enough, two of the closest to the router it happens to most, but not always them) and not always the same ones. And then recently I'm noticing also 1 or 2 of the Wyze cams.
Some settings details:
-
I have all 11 of my IoT devices connecting to a separate IoT network 2.4ghz and I also have each of those set in the Tether app.
-
I've disabled's TP-Link's Smart Connect, per the instructions of the thermostats, as apparently leaving it enabled can cause issues with the connection of the thermostats at times, so I now have separate 2.4G and 5G SSIDs set up for my main network.
-
And finally, I have Device Isolation set to Enabled on all 11 IoT devices, even though they're on that individual IoT 2.4g network.
Thanks in advance for any tips, and please let me know if more details are needed, happy to share if it helps me here and some other person in the future.
Thanks a lot for getting back! And yes you're right, it's 19 IoT devices, my math is that bad 
Since my post, I also gave each of the thermostats a static IP (under Network/DHCP Server/Address Reservation), which didn't help.
But I THINK I may have resolved the issue partially at least...
It turns out the thermostat default client names were exactly the same, which I'm wondering if that's clearly what was causing the issue because for the last 18 hours or so, all devices are staying connected since I gave each of the 8 thermostats its own unique client name in the TP-Link router settings from my browser (192.168. 0.1). Obviously they each have their own MAC address, so I'm not sure if 8 devices having the exact same client name was even the issue, just assuming
i.e.) Product Name is how each of the 8 thermostats were named before, with exactly the same name. I've since changed those to each have their own name by adding the room name AND replacing the space with an underscore (_) so for example new names are in the format of livingroom_Product_Name and office_Product_Name, etc. Does that sound like this would have been causing the issue?
The thermostat manual recommended the 2.4 ghz SSID settings included enabling only 20 Mhz and not dual with 20/40 Mhz. I noticed when I enabled both, I started seeing the issue more often. If I only have 20 Mhz selected, connection to thermostats seems to stay better, whereas when I had both I'd start seeing the connection drops more often. All this said with the router settings, I had attempted them days ago and I saw no change in the disconnections. It wasn't until I changed each of the client names mentioned above that the disconnections seemed to go away, mostly.
Thermostat settings also recommended using only channels 1, 6 or 11 with least interference. As all 3 of those channels become crowded for me at random times, considering my location around other homes, I've left this to automatic.
As for your questions in case it's just coincidence that I have it working so far and that it starts happening again:
So I haven't had to do step 1 or 2 yet
For number 3, the connection is always very good or excellent.
For number 4, I'm on a cable broadband modem for my ISP, which I've disabled wifi on and have my own router connected that. I've had this set up for years with no issues elsewhere any any of my other devices.