Using Chromium at all is supporting Google’s dominance over the market
Of course it does but that is a moot point and a different discussion altogether. It doesn't change the fact that Brave is fully open source, even their shitty stuff and that it's better for privacy than using a proprietary browser like people here suggest. It also doesn't change that Chromium has a better security model than Gecko.
I personally right now prefer FF (Librewolf and Mull) for different reasons still. The Chromium dominance is...well it is what it is. Definitely not the reason why I use FF. It's a losing battle. FF has been losing users forever now. The few % market share it still has will not change that Google is going to "win". When the EU forces Apple to open up iOS for Chromium the last "wall" that is in the way of total Chromium dominance will fall. FF will not do anything about that except just exist until either too many websites break or someone does something about Google controlling Chromium. Until then I'll just choose whichever browser fits my needs in terms of FOSS, privacy but also features. Right now FF is good enough despite them lacking behind in security (severely even on mobile) and I'm happy to use it.