Hi all!
I added my answer in the following branch: How do I set a fastai learner to use the GPU on an M-Series Mac? - #4 by JTaurus
And here are more details: FastAI 2022 on Macbook M1 Pro Max (GPU) | by Ivan T | Feb, 2023 | Medium
Let us know if someone solved Operation 'neg_out_mps()' does not support input type 'int64' in MPS backend. issue 