alt Hacker NewsBrave said they'll try to maintain limited support for MV2 for only 4 specific extensions, but recommend Brave Shields as the go-to adblocker for the future. Google is about to remove most of the MV2 code from the codebase, which will explode the complexity soon.
Brave has perverse incentives to discontinue it because of their BAT crypto business model that rewards looking at ads.
Unfortunately even the fully open source Firefox isn't immune to the pressure from the advertising industry, with all their Google funding and their purchase of anonym.