Hiya TP link (and other users)

Randomly through the use of my ARCHER VR400 V2 my devices get disconnected from the 2.4ghz band and I can't find it broadcasting when I search for it like it's decided to hide but it shows up as disconnected even though I'm mostly in the room where the router is 95% of the time.

The Odd thing is my 5ghz stays broadcasting but I'm not logged into this because of it's short range and I have to add the Wi-Fi passkey to it to get internet.

Even when it gets warm and I've powered it off to go cold and then reinitialize it the 2.4ghz band doesn't reappear,it feels like a firmware issue as when I run speed checks on sites like the fast speed checker on occasion it states my connection is running less than 1mb but the ISP Assures me (via Ethernet tests) that I am getting the full package speeds but multiple devices can't all be wrong can they.

They even accused the router of failing and to replace it.

Any ideas into fixing this will be grateful or even beta firmware to try.