@hedgehog@ttrpg.network according to your threat model, of course.
Okay, look. Chromium's monopoly is definitely a concern. But Firefox is also not the answer here.
@jonah@neat.computer @brave@fosstodon.org manifest V2 is spread all over chromium source. There's definitely a way to maintain it but it'll quickly become a hassle especially between Chromium version bumps. In any case, if they said they'll do it that's still better than nothing.
As for uBlock... I don't think there's anything special to Chromium's version of Manifest V2 that they'll need to support. So it should "just work".