Well, interestingly, coming to this again lol. I would conclude that Invalid Binary is a general term and you need to look for issues, could be permissions missing, app icon issue, package not updated to latest version or something else, but you need to look for reason. This time i got reasons through email via appstore connect.

Coming to this after some time, I am using flutter and faced this again, but this time it was because of my package (connectivity_plus) not updated to latest version. One thing you can do to figure out the exact problem is to upload app manually through xcode as I was uploading through codemagic before and it was not giving us proper rejection reason.