I think I've posted this before, but my bet is that it came from the wet market.
Species that normally do not cross paths were forced together, enabling the established bat coronavirus to be transferred to some intermediate species. It then mutated enough to become the SARS-Cov-2 currently circling the globe.
How it got from the intermediate to the humans, perhaps we'll never find out.
Did it sneeze on the human? Cough? Bleed? Bite the human? Or did the human get it by eating an intermediate?
That's where my tenner is currently sitting.
None of which rules out a release from the bio facility, be it intentional or accidental.