I am experiencing the same issue.
My friend made a picture with iPhone 16 Pro, backed up with Google Photo and shared it with me through this. Once shared, I received a JPG image (not HEIC). When I downloaded this image and added to Apple Photos on macOS 15.0 I cannot make any edits getting this error:

Asked Apple Support for help.
What I noticed, the JPG photo downloaded from Google Photo is with embedded Colour Profile: Display P3.
Not sure if that relevant, but when imported it to GIMP been asked to convert to sRGB which I did and saved in new file. New file worked well in Apple Photos. Tried with keeping Display P3 and re-save in to new file and it worked well.
Looks like this particular image taken from Google Photo is generated in format that is not compatiblem with recent Apple Photos in macOS 15.0 (it was working month ago with simillar way of sharing files).
Something must changed somewhere.
Looking for a solution.