I don't really want to become the judge of what is "heavily-AI-assisted". I think if I were to write a rule I would focus more on self-promotion in general than trying to decide how AI assisted it was. For example something like this:

This community should not be primarily used for self-promotion. You should be contributing to the community before posting any of your own work and a small fraction of your submissions should be your own work.

As for slop or not I would generally rather rely on user votes to decide if it is "worth it" or not. But maybe that is unsustainable and we will need more of a rule. I do think that if you ask a robot to write you a project in 3 days then post it here it is probably not adding much value.

I'm open to discussion though.