FreeBSD13/aarch64 runs on them too!
Yeah, I have stable results running a couple of FreeBSD13/aarch64 pi4b servers. I just use the Raspberry PI Imager app to burn the iso, and Bob's your Uncle.
Mainly running network monitoring and DNS, so pretty light-weight stuff, but perfect for a bit of systemic diversity on low wattage h/w.
I also use them as a cross-platform check that code compiles and runs in different environments. If my applications compile and run on an Intel Debian and a 64bit Arm FreeBSD, I feel pretty confident that I've covered most system dependencies. Important for me as I mainly work in the cli/server space.