I just made the jump from Opera to Brave after ~5 years of dailying Opera. I wasn't hugely put off by the AI popup; in fact, without the AI bits, the select popup was nice to quickly search something. For me the driving factor was Opera's shady business practices of "use our VPN/AI/whatever" and then harvest data from that.

Other than the recent(ish) UI redesign, though, Opera has solid UX. I will miss the interface, but Brave has most of what I want.