Edit: my bad, seems like I misunderstood. PopOS used/is still using GNOME and has a Auto-Tiling plugin that behaves like i3wm (?). I guess this is what OP is talking about!
Not entirely sure what you mean. PopOS, developed by System76, uses the Cosmic DE, which is itself also developed by System76.
River is a dynamic tiling WM which is known for it’s customizability among Wayland WMs, as it doesn’t distinguish itself with it’s “layout generator” (though it does come with a very basic one), but instead let’s the user write their own or use an existing, third-party one. This way you can achieve essentially any dynamic tiling behavior with River.
How does PopOS use a system like that? Or do you mean that Cosmic is DWM-style, i.e., dynamic and with tags?
I do agree that River is wonderful though!
For a long time I used a super customized zsh setup. It was, unfortunately, crazy slow and regularly broke on updates. It had precisely all the features and behavior I wanted though. Like you say, zsh is very customizable.
Then I switched to tiling window managers and with that to the alacritty terminal. This made me value start up times and performance, as I was constantly opening and closing terminals. So I spent a ridiculous amount of time optimizing my zsh config to be as fast as possible. This is also what I used for a long time before correcting my ways.
When that device, my work laptop, failed, I had to set up my desktop for work. This involved setting up zsh, which I quickly realized was a lot of work. So, on a whim, I installed fish.
Oh my god. Not only did fish have nearly all the features I wanted out of the box, but it was easy to add plugins (customizations) in a performant way. Fish even had default behavior I didn’t know I needed. And most importantly: it was crazy fast!
Since then I have never left fish. It is so much better than anything I had imagined. At this point I use way more default features as well, so I pretty much only add the tide prompt and zoxide. I also have a functions and abbreviations folder which is essentially my zsh alias collection.
The crazy part is really how much faster it is though. I really, really love it. And now they’re rewriting it in Rust as well!