When you got this Mac, did you buy it with this version or you upgraded to it? (not like it matters a huge deal)
If you ugpraded you might run into noticeable performance regression which will be noticeable on high demanding games, but largely issue is that the game is not optimally optimized in my opinion with patch 8 in mind.
Kinda ironic how the game ran much better during the beta version of the game but a lot has changed since then, I am no computer expert so I don't know what I can say to be extra helpful but hardware wise you should be fine to run the game on medium settings, but no more than medium as you are kinda meeting the absolute minimal system requirements.
16 GB of RAM is preferably with (M2/M3/ M4) or a more dedicated graphics hardware if you wanted to play with higher settings, specially considering its only partly optimized and hotfix 30 helped but not entirely across the board.
Unless you running into those performance issuse with medium settings already, I'm not sure what else to do than suggest sending a report to Larian via the bug report formate, maybe someone with more expertise with Mac can suggest something.
