[roelschroeven]

They were not really mutually exclusive, but were often portrayed as such. The lab leak theory got confused with the intentionally fabricated theory, probably as a strawman argument to discredit the lab leak theory.

For what it's worth, your scenario seems to me the most probably by far. I don't think we'll ever know for sure, since China has done it's best to destroy all evidence (we should be careful not to take that fact as evidence for one theory or another though).