First, how many people are working on those files? I have more problems with more people.

The main problem are multi files that are all written together, e.g. Scrivener, Git, ... - I get sync conflicts which are hard to solve.

I'm not sure what your use case is, but syncing source code repositories to a shared folder doesn't sound like a great idea to me.

Collaboration on individual files is also best solved using online office suites and similar tools.

The remaining scenarios indeed benefit from file locking and may need conflict resolution from time to time.

"Collaboration on individual files is also best solved using online office suites and similar tools."

Yes, as I've said, I'd use something else, I've fallen for the "Share and collaborate on documents" marketing slogan of NextCloud on their homepage.