Same as any other driver, go to Windows Device Manager, right-click on the device, chose uninstall and tick the remove drivers box. Re-plug. Repeat until stock drivers attach again by its own. Done
I've taken us to a dedicated thread the forums have a private chat but I prefer chatting via Discord (invite link), I have a business e-mail address as well ofc. but that's more for passing documents and boring slow-paced conversations
That should be possible, yes. This software stack doesn't dictate how the controllers get presented to the system, that's a different story and once I've documented the API I've designed in theory any other dev can take those inputs and refine them in any way shape or form
ARM/ARM64 shouldn't be a problem either, I don't have hardware myself to test but I don't use anything explicitly x86_64 specific so should work just fine. Maybe we could test it together.
Since I happen to own a business I can also accept customization commissions
Guys 'n' gals, relax I am here, just not 24/7
SCP driver setup on its own does not and never did manipulate your mouse and keyboard. Period. If your mouse and keyboard are connected via Bluetooth and you install SCP's Bluetooth drivers, then yes, poof, they lose connectivity because that's just how SCP's wireless works. No way around it other than maintaining multiple Bluetooth dongles.
If it happens on USB I bet everything I possess that at some point you ticked your input devices in the driver setup tool (if on version 1.6), that's really all there's to it
As for the errors in the screenshot, well, SCP's development has long been discontinued, it either works or doesn't, sorry
EDIT: I recommend you avoid that trash site imgur, you can just paste images directly into your forum post
Building those submission CAB files feels like ancient magic once you haven't done it for a couple of months but I got it
Mate, there's a literal ton of information about how to read gamepads out in the open already plus you've listed a lot of questions that would need in-depth page-long answers, I advise you utilize the search engine of your choice first before assuming anyone around here will give a spoon-fed answer...