No clue what device are you playing on, but you can just play on browser!
hii, what mac users do with itch io games (including myself) is click 'done'' instead of 'move to trash' after the usual message pops up and then go to 'security settings' (you can search for it in settings). there's a button that says 'open anyway' and you’ll see something about apple not being able to verify the safety of the game. it’ll ask for your password or something, and then you’re done. it’s completely safe
an alternative is downloading the itch io app for mac to get it directly from there (like steam) so you never have to deal with those kinds of warnings again. no message or anything