I have found a workaround for running KStars under RPi OS 64 bit bullseye when your USB devices include an FDTI USB serial interface. I was having problems with some USB devices not being found by Ekos, notably as it happened the guide camera and a ZWO EAF. I installed KStars 3.6.6 using Nou’s script gitea.nouspiro.space/nou/astro-soft-build .The workaround as described in github.com/raspberrypi/linux/issues/3779 is to run ‘sudo apt remove rpi.gpio-common’ in a terminal window…… of course this disables GPIO which may be inconvenient if you have an RTC or GPS connected by the GPIO…..