Problem 1 is also largely solved by ditching GitHub in favor of an environment where you control who is allowed to submit a PR. GitHub is convenient but if you have problems with vibe code volume, choosing to host with a company who heavily incentivizes it and has a commercial interest in doing so is self-defeating. Treat it the same as any other free service that enshittified after several years of market capture on the basis of being free and convenient.

Problem 2 is the actual reason the project tanked and your take is spot on.

I personally vote for being polite and cordial. Patiently wait for them to finish, then swat the camera right back down with a baseball bat.

Smile, then offer them the baseball bat and invite them to take a swing.

Department of War Crimes

Why not both moment:

Micro$lop