Yeah, as far as I can tell, all of that works. As mentioned above, I can switch to CSL-JSON and back to BibLaTeX in the plug-in settings and all the new references are there. I can also do the dreaded “reload without saving” (approximate wording), and the new references show up. Also, as I said above, I don’t see anything in the console stating that the plug-in has tried to reload the .bib file.
I neglected to mention I’m running macOS Big Sur.