@ShaunJR 

I don't think it can be turned off completly. Set the QoS to standered and toggle off any client that has high prority on.

After doing this my speeds returned to normal. It is diappointing I brought up the issue of the Tether app slowing down my speeds and the same tech support

that replied to this thread acted like it was a new issue.

I moved on to asus triband ax router and no longer have buffer bloat .

however one tweak i did for qos downlod/upload was set my rates to 90% of isp. Shot in dark maybe it helps orher gamers with bufferbloat (dsl reports speed test)

isp rates are 200 down 10 up.

on new asus router i set it to 190 down 9 up and bufferbloat resolved. Possibly this trick works on tplink?

for those with speed issues:

2.4ghz use 40hz not auto or 20 ... more interference but less buffer bloat. Try air time fairness as well due to legacy devices turning off network.

try to retire wifi G only devices in house.

for 5.2ghz i set mine to ax only but more importantly use 80hz (faster) and not auto, test 160hz the fastest but make sure its not having a ton of interference.

lastly if u want ax speeds get an ax wifi card from tplink or asus (both use intel ax200) for desktops or get the intel ax200 (killer nic x1650 is the same chip a little custom)

Also most routers have worse rates through walls and over distance.

Good to see I'm not along on this. I was getting great internet speeds with my TP-Link touch p5 around 245mbps.  After 3 days my AX 3000 went from 218mdps to 90. Thought I was doing the right thing by telling it to reboot daily when there's no activity in my home. I did reinstall my p5 and my network speeds are back.  Hopefully there's a firmware fix for that.

@Carl . I hv been having speed issue with AX 50 router. Tried many different ways. Nothing worked. 
 

saw the answers Here. Decided to give it a go and it has worked. 
 

Had to reset the router to factory settings, deleted tether app, logged in via any internet browsers, and maximum speed achieved. 
 

i am attaching photos as proof. 
 

tP link needs to look into tether app. 
 

What the hell is going on here, what's taking so long to fix this issue?  Is the device defective, need to exchange it / refund, what? This thing starts of GREAT, pushing 600+Mbps on my 1 Gbps line, but then after a day or two, BOOM, download speeds of 80-90 Mbps. W..T..F..?!?!?!  I returned the Spaceship $500 Asus router, after seeing how great this one performed, but little did I know the headaches I'd be having soon after. TP-Link... Any other firmware upgrades, or should I just send this piece of trash back?  I can confirm that installing tether app initially caused the slow down, so uninstalling / resetting to factory would do the trick, but I believe after the most recent firmware upgrade, problem comes back even without installing the damn tether app. You were doing so well there, TP-Link...

@Carl . Thx for your prompt action. Great . I loved the flexibility of Tether app so eager to know once it gets sorted. I am very sure many people complaining are from US so issue remains the same on both sides.

Firmware version (AX50): 1.0.8 Build 20200426 rel.65338(5553)

I've went through the 6 pages. Below are a few things I've noticed.

Tether crashes the router:

If I set a client to be high priority on the router, the router crashes & reboots

Slowdown when QoS is enabled

Once QoS is enabled, even if the bandwidth is reset to zero, it's not truly disabled.

During the speedtest, the Mbps meter will slowly (starts in the 60s Mbps) crank up to my max (150 Mbps).

After a factory reset, it starts off right away at 130Mbps, and makes it way to the max.

Feature request:

While I believe the issue is how QoS is implemented by tp-link, can we have the the QoS settings enabled on the router itself & not via the tether app? This will help us rule out the app being the issue.

A thank you:

Thank you to the tp-link team for fixing the issue where Dmz / virtual server was not working properly. This affected the Xbox quite badly.