The first game was so much fun!

Please check out Apple's new game porting toolkit. It's simple enough that many regular users have been using it to play AAA games on their Macs without the aid of the developers.

https://developer.apple.com/games/

Would be great for this game to run on Mac. Windows is a pain to use and to boot just for this game.

From what I can tell, based on all the UnityEngine.dll files, this game is made in Unity, so porting is not the problem.

However, publishing a Mac build would require testing it first. It's quite likely that at this point, the dev team is too busy finishing the game, rather than wasting time testing multiple builds, as testing is a very time consuming process. It makes sense for them to focus on the Windows build until the game is no longer in early access, then test the game on Windows, macOS, and Linux, before releasing all 3 builds together.