There are always going to be limitations to extension-based approaches but Firefox with tridactyl is most of the way there capability-wise IMO (https://github.com/tridactyl/tridactyl). I use that plus tree-style tabs and find it excellent. There's always some extensibility limitations that break the integration though, like extensions getting disabled on mozilla domains.

I love projects like nyxt and respect their priorities, but without big-player extension support it's usually a no-go for me. Still, I'll be interested to see the ideas they develop trickle out into the rest of the power-browser ecosystem. I especially like that lossless tree history – history management is a very under-explored UX area IMO