I use Firefox exclusively for everything except web development (Chrome) and for the one site that doesn't work well with Firefox (for that I use Safari). Safari is way slower than Firefox, has significantly less extension compatibility, no support for tree style tabs, no support for a proper open source ad blocker like ublock origin, little to no extension support for advanced privacy stuff like auto cookie deletion, etc. the list goes on. Also Safari updates are tied to OS updates, I can't get new Safari features and security updates if I choose to run an older version of macOS. Given how completely dog manure the latest macOS versions have been I have to wait 1+ years before upgrading OS versions. E.g I will start thinking about upgrading to macOS 13 by the time they show off macOS 14 at WWDC.
The only thing Safari has going for it is iCloud support (shared tabs, tab groups). If Apple fix up all my listed problems I might consider switching to Safari because I like the iCloud feature set.