Within the sqlite project we're fairly convinced that FF and Safari will catch up as soon as their larger customers start targeting Chromium-based browsers simply for the OPFS support. My estimate is mid- to late- 2023 at the latest. My (mis?)understanding is that Safari has most of this support but not the latest changes from Google (namely "sync handles"), and sqlite needs those latest features in order to use OPFS.
> Very excited to try this once support is added to Firefox and Safari!
That's up to the browser vendors, but it seems very likely that they'll jump on board once large apps start making use of it OPFS (independently of whether or not those apps use sqlite). If their impls are API-compatible with Chrome's (which Google is certainly pushing for), sqlite will "just work". It is likely that the OPFS APIs will be tweaked somewhat in the mean time (e.g. changes in the locking-related support are under discussion), and sqlite's support will/would need to be adjusted accordingly, but "one of these days" it will "just work" across the 3 major browsers.