This sort of thing can be done, but it takes a lot of work to coordinate everyone. Try to keep it as small as it needs to be so it doesn’t spiral into an unfinishable procedurally generated VR MMORPG dwarf fortress / factorio pyanodon / no man’s sky hybrid with AI NPCs, puzzle platformer elements, and ActivityPub integration.

You can look at Thrive, which is an open source C# Godot game aiming to be a scientifically accurate Spore. It has a really huge scope and has been in development for more than a decade. But at least they are working on it mostly one stage at a time, so it starts as a relatively small but complete game and grows from there.

And if you don’t have a specific idea in mind, you might be better off contributing to existing open source Godot games. At the least look over existing projects so you’re not duplicating effort. You might find one that you can fork into something new.