patch 1.10.3 (Big Sur Fix) resolved the game not starting issue.
🖥 1080p
🖥 1440 × 900
⚙️ default settings
Smooth (at least 30 fps) in 1939 at the start of the war - unsure about late game, Didn't work before the November 26 update - may need to delete any files apart from saves generate in the user folders. Comes up with a warning on the Paradox launcher but still launches fine.
🖥 2560 × 1600
⚙️ Maximum (also default)
🖥 1680 x 1050
⚙️ default settings