Also having issues with terrible slowdown when going through photos once they are imported. While importing, it's almost impossible (it was always slower when importing, but I think that was noted earlier in this thread that it's normal behavior). I have not, however, noticed longer import times. Once the import is over, sometimes it's terribly slow, almost unusable, to page through the photos. Other times it's almost back to normal. Doesn't seem to be any rhyme or reason for it, but it's slow more than it's fast since updating to Ventura.
I will note, I have three computers. My M1 MacBook Air is the one I use most, and it has this problem off and on. My 16" MacBook Pro M1 Pro would only work slowly, it wouldn't work at normal speed. My 2017 15" MacBook Pro with Intel seemed to work normally with no issues. I didn't use it much though, as I don't really use this computer anymore. I shoot hockey too, and was tried the 15" for a game just to see if it fixed the issue.
Is it possible it's an M1 Ventura issue?