I have been able to install Raspbian 64bit (bullseye); I then added astroberry repo.
That way I was able to install PHD2 and kStars (bleeding: 3.6.0) which are in the astroberry repo.
At first, kStars crashed, but following a trick I found in a german forum in which they where discussing this installation (www.indilib.org/forum/astroberry/12390-6...rry/reply/86978.html), I removed kstars-bleeding, installed the standard kStars in raspbian, started it with a simulator profile, and then installed again kstars-bleeding - it worked!
Anyway, I'm still configuring the system but it seems to work, and without compiling a thing.
I don't know whether the packages are being built right now, the 3.6,0 64bit version I got installed corresponds to Build: 2022-08-27T18:31:54Z