I’ve been using CachyOS for about a year on a T2 macbook air and a key I use to input both my LUKS password and my account password are nonfunctional.
Now I have no idea how to access my files and external keyboards don’t seem to work.
Thanks in advance
Wow, no ideas then… I was going to suggest picking up the cheapest nastiest local DIY store plastic wonder - that kept me going between my last Logitech failing and buying my current tri-mode Ajazz (wired/2.4/bluetooth).
Oof, sorry to hear. I don’t quite know how T2 deals with these things, but if external keyboards don’t work then you may be best served by just prying out the damaged key (it’s not too hard to do with some tweezers and a pry tool), and trying to either replace it, or if you can dig around in there enough, shorting the two contacts underneath to trigger a “keypress” for you to be able to enter your password.
Good luck!
This is where this is an advanced mess, I’ve pried it off a few monthes back and cleaned it up, but the shorting trick no longer works.
Thank you though 
Anyway I’m looking at a framework 13 right now
It’s surprising that external keyboards don’t work. They should.
I routinely use a wireless keyboard via usb dongle to log into a CachyOS system, works fine for entering LUKS decryption password in plymouth and all.
Have you tried different keyboards? Different USB ports? Wired vs wireless?
Maybe there’s some kind of BIOS settings inhibiting it?
In any case, you should be able to get to the files on the machine by booting a LiveUSB and mounting the internal drive. That would allow you to access and exfiltrate important data.
If the laptop is meant for the dump, opening it up and taking out the drive (to add to another system) is also an option (and something you’d probably want to do in any case).
The keyboard I used being very old may have been the cause, I will try with a newer one at the store
It’s always worth having at least one nasty cheap plastic monstrosity tucked away somewhere for emergencies whilst you take time to work out your next ‘forever’ keyboard.
I’m happy with my Ajazz, I picked up some cheap tactile/silent switches for it, and 6 months later a nicer set of creamy PBT keycaps and it’s superb, as long as you don’t mind the tradeoff of dirt cheap meaning the software sucks… not that it’d work with Linux anyway.
Oh, and annoyingly, if I hit Fn and Meta, it locks the Meta key (gamer function) which is annoying, as I would have liked to use a whole set of shortcuts with that basis.