> All other browser I've tried (firefox, vivaldi, edge, safari, atlas, many others) and all other programs with a tab-based UI I use (zed, vs code, sqlitebrowser) look worse.

Both you and the poster could both be correct.

Looking good and being a poor interface are unrelated.

IOW, something could look absolutely beautiful and still have a nightmarish UI.

"Looking pretty" is subjective. Being a good UI is objective.