I purchased the Steam version and played it, but the most recent Mac update makes it impossible to play 8-bit games on Steam. Do you know if the Itch.io version would work on a Macbook Air, and if so, could I transfer my steam file onto it?
I think newer macOS versions tend to have issue with RPG Maker MV games although I don't have a Mac, so I can't verify if even Apple Silicon Macs can run MV games. There is this post Regarding Future RPG Maker MV macOS Support that mentions that MV won't support macOS 11+. RPG Maker MZ games should work although Didnapper 2 is an MV game.
I don't know if MV games are 32-bit on Mac since they are on Windows (RPG Maker MZ is 64-bit only). I know it can be confusing if a Mac app is 32-bit and 64-bit. For example, Discord is 32-bit on Windows while the Mac version is 64-bit.