macOS-native vertical tabs were a big win for me too, and like yourself, its WebExtensions API is a win over Safari OOTB but there are Chrome extensions I really rely on that don't work, some as a result of the differences between Webkit and Blink themselves, so I find myself drawn to Arc browser where I get, IMO, a much more robust UI where vertical tabs are the default and the command palette in place of an address/search bar is on the money.

Orion is about to release in-place window switching that sorta matches up with Arc's behavior, but I still prefer Arc as the command palette UX, as well as being able to use back/forward mouse buttons to switch 'in-place' windows, is just the superior affordance.