I agree that acknowledging a lab leak and its catastrophic global consequences would be "existential" for the CCP.

The best that can be hoped for, in my opinion, is to forego affixing blame and to establish new international protocols for labs researching pathogens. Countries would sign on and agree not to conduct joint research with non-signator countries. That way, Beijing could sign as a blameless global citizen and because joint scientific research is in their own interest. If it was a lab leak, I suspect they know by now (with full access to patient data) and are as fearful of future accidents as the rest of the world.