I managed to build kicad from macports tonight. It compiled and it works (seems so as far as I can tell, being a Kicad newbie).
Since I’m bound to stay with macOS 11.7.10 (BigSur) due to old hardware maybe, it could be an option to build 9.0.1 (under macports). Or would there be other be other ways to run 9.0.1?
EDIT: I was so keen (too keen) to download the DMG from the kicad download site. Though it is said that it is for macOS 12 I tried. Unpacked the DMG, overwrote my existing working Kicad 7 installation. My bad.
Repaied the situation meanwhile by reading in a backup.