The BANAL viruses collected in Laos are closer than RaTG13. No published virus is close enough that SARS-CoV-2 could readily be derived from it in the lab, though some people have speculated about pathways via accelerated evolution during serial passaging.

I believe the most likely research-related origin involves an unpublished virus. I don't think that's implausible; the WIV was also sampling in Laos, and no research group in the world has published literally everything they're currently working on. Even with no attempt at secrecy, it takes time to write stuff up. It's also possible that SARS-CoV-2 is a naturally-evolved virus collected and leaked by the WIV before they were able to sequence it.

As to the grandparent's final question, I'm not aware of any serious claim that Pfizer had anything to do with this. There was a claim that Moderna was somehow involved, based on a genetic sequence that appears both in SARS-CoV-2 and in a pre-pandemic Moderna patent; but that sequence appears in other previously-known organisms too.

Thanks. To clarify my question, the part about Pfizer seems to be that they were engineering virus variants after the pandemic started, and doing so intentionally in a laboratory, not (merely) as a byproduct of overly-specific vaccines exerting evolutionary pressure.

What I heard about that was based on supposed leaked information (Project Veritas). Such information going public would obviously be very bad PR, so it would make sense for it to be secret, if it's real. But also, anyone can record a fake interview (and nowadays, somewhat convincingly replace the faces and voices too), so...

Ah, the video with Jordon Trishton Walker--so not the virus origins, but alleged gain of function work after emergence. I understand that the video is real, and he really is (or was) a "Director of Research and Development" at Pfizer. Most of what he said was scientifically incoherent, though. I'd guess that he got the job for internal political reasons, and that he has almost zero influence on or even understanding of whatever Pfizer is actually doing. I don't love fact check sites in general, but this one has some quotes from researchers that are consistent with my judgment of his expertise:

https://www.factcheck.org/2023/02/scicheck-no-evidence-pfize...

I'm not aware of anyone developing vaccines targeting laboratory-enhanced viruses. GoF proponents sometimes cite earlier vaccine development as a possible benefit, but even they don't actually fund such work--the mutations that occur in the lab aren't predictive enough of the mutations that will occur in real human spread to justify the speculative investment. The research of concern is pretty much all in academia, basic research with more nebulous intended benefit.