For me, I really want to get into niri, but the lack of XWayland support scares me (I know there’s solutions, but I don’t understand them yet).
Also, I stopped using Emacs (even though I love its design and philosophy with my whole heart) because it’s very slow, even as a daemon.
Seconding Sway. I will admit I prefer autotiling (switching the split for new windows between horizontal/vertical automatically, rather than choosing which split you want), but overall Sway is so good in configuration that I still use it in spite of being a manual. The configuration takes time, but that’s common to pretty much any tiler.
Thirding sway, although I use it with gnome. It’s a very good first choice for a tiling window
Fourthing sway, specifically swayfx and (as someone already mentioned) autotiling, both of which are available in the Nix repository without hassle.