I don't even have an online bank acount don't worry (most my games are set to 100% money to itch.io), this is a side project anyway i come back to it when i'm sick of working on my main game. Thanks it's really nice of you though. However, I don't think you can help me because the base project is very old and messy (i have a hard time navigating my self it even if i made it) and i don't know how to work on the same project from different computers on Game maker: studio. What I do appreciate is suggestions of stuff to add (it may take time to add them because this is a side project).
I understand the problems tht may cause and for sharing files i suggest either trello google drive or dropbox depending on what you are going for and as for help honestly messy code isn't always bad but i do suggest adding a few comments and keeping it a bit neat so you understand what you were thinking where you were and where to go from there i'm also working on a game we even made our own subredit we just don't have a public version yet and don't know how to encript the files so it can't be pirated XD
also i saw you were learning a bit of unity if you like i can try and teach you what i know but i don't really know much : )