Also, Intel denoising does not require an Intel CPU, that is just the name of who made the denoiser, not what it runs on (unlike the NVIDIA AI denoiser which was both created by NVIDIA and DOES require an NVIDIA GPU). That said, I don't have an M1 processor, so can't say whether or not that denoiser runs, but I don't see why not (it runs on my AMD machine just fine ;) )
EDIT - and of course there is always the Corona High Quality Denoiser too, anyway.