Wifi won't connect in debian

[Simon Wooding <glasfryn27@gmail.com>]

Hello,

I have a Lenovo Thinkpad which I used to run Windows on. A few days ago I installed Debian 10.6.0 (first as dual-boot to make sure I could transfer everything, later deleting the Windows partition). I had to install non-free firmware to get wifi working during install, but I found the required drivers on Intel's website and everything went smoothly from there. Fast forward three days problem free and when I booted up this morning I had lost some of the graphical features of my desktop environment MATE (the top/bottom panels, my chosen theme, and a number of keyboard shortcuts no longer worked) and I couldn't connect to the internet. I don't know if these problems are related, but I can't fix the desktop environment without internet access so it's somewhat moot.

Clarifications on the internet problems:

It's not my provider, that's been working fine all day on other devices

It's not a hardware fault; while I was trying out stuff to fix it I tried using my boot-repair live usb to see if the hard drive was the problem, and while in that mode connecting to the internet was easy and worked fine.

I'm not sure what difference using ethernet would make as I can't figure out how to connect using that either but I do have access to an ethernet port if needed.

I have tried a number of suggested solutions online, but none have worked and I couldn't try a lot of them because they required packages I didn't have and couldn't install offline.

I need wifi access back fairly promptly as I am a university student studying remotely, so any help is thoroughly appreciated.

Thanks,

Simon