I've worked with files much larger than that with 8GB and 16GB on lesser machines. You don't need more than that, unless you have people frequently calling you asking where the work is.
I worked with 300mb and larger files on a Powermac G5 with 8GB back in the day. Have used 16GB since 2012 without issue. Don't know why you're having issues with an M1 and 16GB, but I never used that machine. Photoshop is a RAM hog, but 16GB should be more than enough.Hi I can only tell you, I am working on an M1 with 16 GB and my files can hardly be edited because of the size. So your answer is hard to understand for me. Adobe has looked at it for itself on my Mac and they also said that the 16 GB of the M1 are no longer enough to work smoothly
Did you have the 24 Core oder 32 Core?I frequently do enormous panoramic stitches of 20+ images using 45 to 50 megapixel cameras in Photoshop, and which usually result in approximately 400 megapixel final images.
I have a 16" MacBook Pro M1 Max with 64GB of RAM. My RAM pressure is usually around 75-80%.
If you're going to be primarily working in Photoshop, I honestly wouldn't get anything less than 32GB of RAM at this stage. If you're in a position to upgrade to 64GB of RAM, I would.