Cool story bro. And I am one of the 9 people that worked on the team at Intel to implement your modern EFI/UEFI.
I just don’t have the time or energy to sit here and explain the whole fucking stack to a bunch of people who mostly could care less. But, Secureboot, it’s a good thing, and the tools on linux get better every hour. Check out lanzaboote.
This fucking bug is not new, and not special to KDE. It’s because there’s missing documentation in a lib just above Wayland, so it only affects some apps that aren’t using a higher level toolkit, Firefox is in that box. The bug is literally 8 years old and would literally require one fucking line of code to fix, but the cunts over at freedesktop refuse to merge the changes. If I were at my main computer I’d send you the link and details.
One thing that sometimes fixes it, is the menu key next to the spacebar.