I built something like this years ago. It's just on the edge of roll-your-own-solution.

I definitely agree with your approach of auto mocking the database and/or third party services too. That's what I did with my home rolled solution.

Happy to see more projects in the space. Generating tests by snapshot including the DB and service calls always seemed like the obvious way to go for me.

As a dev I'm not keen on using services which I could easily replicate so this would have to be both substantial and cheap/free for smaller teams.