@Trekkie00
No, on EndeavourOS I didn’t use KDE. I used there Gnome and tried also XFCE.
I’ve now another problem to solve. Because I thought, grub will automatically create dual boot, to choose
between EndeavourOS and Manjaro. The partition is now divided in two halves. At the moment I can’t access EndeavourOS to install KDE also there. Have to check how to get a dual boot. I think the way achieve this is via grub.config. But I’m a little bit afraid to make a mistake there.