Just a happy user and not affiliated, but Brave was a hallelujah-moment for me. Never got Firefox to be especially fluid, not even close to Chrome. But Brave, IIUC, takes Chromium and adds some adblocking. It's not perfect, and some ads makes its way in, but it removes quite a lot while still being very snappy. To the best of my knowledge and experience, I can really recommend it.

Now I just hope that Brave doesn't turn out to be too evil :S.