I've meant, was that BETA FW given to you regarding the same issue ? The other thing I could think of is to try switching off OneMesh feature if that FW has a dedicated switch button.

Did you approach TP-Link regarding the same issue ? I believe you can install the latest official FW if you suspect that the BETA FW may causing the issue. I didn't ask but is it an EU version ?

It's a good idea to test the DSL with your ISP. A test with a wired device is also a good approach when you have spare time. Other than that I can't think of anything else.

@Robinson_Chera I've meant this setting: Why do you think you have a beta FW, where did you get it, via online upgrade from the device's WebGUI or from TP-Link website ? What's your ISP internet...

I don't see why not as long as you connect the router LAN port to the LAN port of the PoE injector. It should be universally compatible. BUT don't connect the PoE port of the PoE injector, when it is...

@paulcanning Try to connect your desktop by wire to the modem directly and test if there are internet disruptions. I presume you are not using Reboot Schedule feature: