If it wasnt encrypted you could have used testdisk app but I dont see how you could decrypt it in this state

If there is a problem with memory, windows wouldn’t have worked too.

Highly doubt memory is the issue but doesn’t hurt to check

Errors and Warnings obviousky.

you coukd redirect the output to a file

sudo journalctl -e > log.txt and upload it sonewhere for us to check

I couldnt understand what exactly is KDE gears? If it fixes bugs in KDE, why those bugs are not fixed directly in KDE code?