well, mapping is a social game, you'll need to find people who will map a collab with you or just let a post sit in the beatmap projects, bumping if it gets too buried, until someone is interested.
People will likely check your mapsets on your profile to see if they want to work with you, so mapping more and proving that you can make decent maps could improve your chances.
trying to make a collab map because you didnt like how your first sets turned out seems misguided to me though, honestly better off looking for help improving your mapping instead. Most people aren't going to judge you for your first sets being bad, basically everyone's first maps are terrible, and if they do make fun of you feel free to ignore their input, because its probably wrong.
(Edit: noticed you're trying to make an hour long collab, imo you should wait on something that ambitious until you have mapping friends you know are down to help and will actually finish, and until you're confident in your own mapping.)