Given your workflow description, especially larger panos, I would suggest removing the MacBook Air (any version) from your list of options. Why?
I did some tests using 4 of the Macs that I have here. The pano comprised 11 Canon EOS R5 images
MacBook Air M3 8 Core CPU, 10 Core GPU, 16GB UM = 126 seconds
Mac mini M4 Pro, 12 Core CPU, 16 Core GPU, 24GB UM = 38 seconds
MacBook Pro M3 Max, 16 Core CPU, 40 Core GPU, 64GB UM = 24 seconds
Mac Studio M1 Ultra, 20 Core CPU, 48 Core GPU, 64GB UM = 25 seconds
I don't have access to any MacBook M4 Max, but based on trutworthy reviews such as the site you provided a link to, I would expect the lower speced M4 Max to be similar to above M3 Max and the higher speced M4 Max to be 15-20% faster for pano merge
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