Hey, lead dev of the game here!
I'm a bit late, but the engine only supports exporting to Mac of the two, and exporting to Mac requires having Mac hardware, and having Mac hardware requires space and money I don't have.
Mac would, as a result, be financially unfeasible at best, and at worst the game might flat out not run properly on it.
Linux, meanwhile, Clickteam Fusion does not at present have a Linux exporter at all. However, while I haven't tested it, I see no reason the game wouldn't work with Wine, or, at worst, Proton! Heck, I think I remember a friend managing to get the game working on Mac using Wine at one point with relatively few issues...?
The game does have a demo you can use to see if you can get Clickteam Fusion games running in Wine and/or Proton (the latter I think requires running the game through Steam I should note)! It should be a way to then also gauge if the full game will work in those, though I think it was compiled in a slightly earlier Fusion build than the full game from what I recall so I can't make guarantees there admittedly.
Sorry that this isn't the answer you were probably looking for. Just, kind of the reality of things right now.