There isn't any real inherit project structure. Opinionated frameworks often work better with multiple people involved.

Isn't every project an ad hoc opinionated framework? You can do code reviews etc to get some alignment and not have everyone working against each other.

No, every project certainly isn't opinionated. There are a lot of approaches you can take to get there but I wouldn't recommend discussing alignment after the code is already written and trying to get large groups to agree.