I did start a bootstrap for ARM64 some time back, but got stuck on libatomic (an issue introduced in newer gcc, but I think they might have fixed it in gcc13).
For some reason it didn’t find libatomic, and using gcc flags to force using atomics directly either in the haikuports bootstrap gcc or the build jam didn’t solve it.
IMO I think that we should skip libatomic as it adds overhead and almost all ARM boards going forward has the LSE extension, so why add the indirection with a function call overhead. Anyway I am just waiting a bit until most gcc13 problems been found, before retrying.