My ac5400x is acting weird, my 2.4 wont show up or allow devices to connect to it, when I connect my 5ghz to my phone i notice the link speed is slow and should be way faster but on my tablet the...

I seem to be having an issue with my tpllink ac5400 v1, the WiFi is very weak when I'm in same room as router, I've tried changing wireless channels, rebooting and restore to factory, my devices seem...