PopOS is Ubuntu LTS so it's only getting ancient KDE Plasma and no, not worth it.

Aside, yes it’s fairly easy, but you might need to change couple of settings regarding theming and then roll back to defaults to un-fuck some desktop theming.

But I've broken so many systems by fucking around a bit too much.

If only there were things such as KDE based distros and Atomic ones.... (Also what does this have to do with KDE)

but how do you do it safely

Sudo apt install plasma plasma-utils.

and still keep compatibility with your distros updates?

Sudo apt update && sudo apt upgrade