I work on scientific software, so the biggest technical issue I face day-to-day is that OpenMP based threading seems almost fundamentally incompatible with M1.
https://developer.apple.com/forums/thread/674456
The summary of the issue is that OpenMP threaded code typically assumes that a) processors are symmetric and b) there isn't a penalty for threads yielding.
On M1 / macOS, what happens is that during the first OpenMP for loop, the performance cores finish much faster, their threads yield, and then they are forever scheduled on the efficiency cores which is doubly bad since they're not as fast and now have too many threads trying to run on them. As far as I can tell (from the linked thread and similar) there is not an API for pinning threads to a certain core type.