Yeah, I've capped mine at 40 now as suggested and I'd be very happy with that if it was smooth, but it's not. It feels a bit better than it was uncapped but it's still stuttering.
I also have an M1 Max and was having the same issue as you. I think we both posted on r/macgaming as well. So I think I have a solution, I've had no issues since doing this.
- Ensure you're in performance mode in the energy settings
- Use Mac Fan Control to ensure the fans are at a constant 3500rpm (or higher) - I found that to be the sweet spot
- Play at Native resolution / 16:10 (assuming you're using the machines display) or whatever the native external display is
- Fullscreen mode
- Seetings high, no FSR
- Frame limit 40fps (if on internal display) or 30fps if on external 60hz display
This works for me. The issue seems to be if the screen resolution is not the same as the game resolution or in the same aspect ratio. You get a long lag every half second or so which is unbearable.