Interesting, I never even knew Brave had that stuff built in, i switched from Chrome years ago and installing ublock origin had already just become the default thing I do to any browser first thing by that point. Though I will note this line in the link you provided:

For as long as we’re able (and assuming the cooperation of the extension authors), Brave will continue to support some privacy-relevant MV2 extensions—specifically AdGuard, NoScript, uBlock Origin, and uMatrix

Which suggests that they're planning to eventually be forced into Manifest V3 (or something similar) to gimp those extensions, but I s'pose I'll give it a shot without ublock and see how it goes. Firefox has given me trouble in a bunch of ways (not remembering per-page zoom, hotkeys changing on me unexpectedly, issues with reddit/lemmy on long posts, etc) and I wouldn't mind switching back.