I’d rather not use a computer at all than use GNOME for the rest of my live.
For me it’s KDE Plasma all the way.

Does KDE’s Dolphin suffer from this, too?

LUKS does offer multiple key slots. You can have the OS unlock it with a keyfile and be able to manually unlock it with a keyphrase when you don’t have access to that file.
I’m not sure if you can tell the OS to unlock it with a passphrase on boot like with the root partition.

https://lukakopajtic.com/independence/

You can always have a copy of the keyfile somewhere else, on an USB drive for example.
Alternative is to also add a passphrase to the /home luks partition.

pipeviewer or pv

What am I seeing here exactly?