Thanks for the reply @posila, I'm glad to see we're on the same page now. Great to see you sharing all your plans and updates with some rough timelines.
To reiterate, I'm on macOS Sonoma 14.5 on an M1 Pro (stock), hooked up in clamshell mode to a single external LG monitor ultrawide rendering at 3840 x 1620 (using "BetterDisplay").
In my case, I have actually been able to play the game with minimal issues with Native Resolution disabled (I never had it enabled) and importantly Wait for VSync turned off. When I switch that on the game instantly drops from a pretty stable 60FSP to ~30FPS at the point I am in the game (50 hours, Gleba). This stutter is similar to the one I recalled on Navuis a few hours in. I toggled Vsync off at some point in the run and that's probably what fixed things for me. So maybe that's an interesting lead. Let me know if you want me to toggle some more things or play with rendering options to get more info.
If you ask the community for more detailed things to test or logs to provide, I bet we'd be happy to give that. People in this thread seem to be under the impression they've given more than enough data for a repro when it sounds like that isn't the case. Some specific requests would be great.