Everything on Xbox One "taking too long" and no controller pairing

My Xbox One (about a week ago) has developed a couple of faults.

It won't connect to any controllers wirelessly, and on the few occasions where it does, it disconnects after about 45 seconds or so. I can only use the controller if I use a cable, and even then the Xbox One response to button presses or GUI navigation is slow to non-existent. Although after some testing, I get about 3 min of uninterrupted controls for about 2 1/2mins, so as long as I'm quick I can get things done.

Every app/game I attempt to start (especially Settings, recently) just hangs, then I get a black screen with some seemingly obscure error code saying: "[APP NAME] took too long to start" - And I get booted back to the dashboard.

I've tried all the recommended 'fixes' - Cold reboot. Unplug everything and leave it 30 seconds (I even left it all night last night). Ensure all my controllers batteries/battery packs are fully charged. But nothing helped.

Last night I gave up the ghost and performed a Factory Reset, hoping it would fix the issues, but alas no, I'm still seeing the same issues.

I'm almost out of warranty too, think I've got a few days left.

What can cause this, what should I do ?