Thank you for your answer !

I was looking at pop os, and apparently KDE can be installed the way you suggested, however that might create some instabilities, that’s why I slightly prefer distributions that have KDE by default.

I guess i’ll stick to Manjaro then. It’s probably not perfect, but I like it.

Thanks for the advice on the partition. If i’m correct, I won’t have to modify anything besides sda4 and sdb3, so I guess I should be fine