how many games do apparently run natively

From what I understand, indie devs mostly just check a box in their engine's build script to compile the game for MacOS. It's rather the big boys who always have trouble porting their games anywhere due to bespoke engines, anticheat or whatnot. And also sim racing devs for some reason, those never support anything but Windows — even though Feral has ported F1 games to Mac and they worked fine.