Labs are the places where people go to push the boundaries. If we go with lab-leak, it is extremely possible that they had figured something new out. They were doing something novel in there, because they were paid money to do novel things.
It would be trivially easy for a hostile power to covertly release a pathogen in another country.
It would also be trivially easy to engineer simultaneous release in multiple locations.
It would be less easy but not impossible to take an existing pathogen during a pandemic, engineer a variant, and release it in another country.
There would always be ambiguity and uncertainty about the source, because there are no telltale markers that unambiguously define an origin, or even whether a pathogen is natural or man-made.
I am not suggesting any of this happened. But I am pointing out that biowarfare has some unexpected covert possibilities.
While Covid may or may not be an example - insufficient data - any defensive strategy should consider the possibility that some other pathogen might be seeded deliberately.
I would say that it's more likely that this was a natural mutation that got its chance to survive natural selection because of the lasting and intense contact with human researchers in the Wuhan lab. There are some media sources that show that researches didn't take too many precautions with avoiding this contact. E.g. there are pictures of researchers without wearing gloves and one that's even showing bites from bats.