In theory. In practice, Manifest v3 (the changes to adblockers) will be implemented at the C++ level, meaning you'd need to fork Chromium in order to avoid it. I would be surprised if Brave even had the engineering power to do that. Microsoft perhaps, but I doubt they actually will.
I think the parents comment's argument is that since it's based on chromium it also can eventually be forced to acquiesce, so any chromium-based browser is just a stop gap solution.
Chromium is Open Source, Google can
t force Brave or MS or anyone else to do anything they don't want to. Google can make their life difficult, leading to a fork, but they can't force anything beyond that.
With all that said- I still prefer Firefox and think it is the best choice right now for the Web.
The difference in scale of effort and money/time of being downstream vs a fork makes it at least possible that they would do no such thing. I personally think it would be extremely unlikely they would fork it.