I can recommend trying out any non-standard WM to anyone looking to learn more about what's going on with a Linux desktop. I learned more about Linux playing around with TWMs than any other class of software.
I don't know if it's really made me any more productive, but it's a fantastic learning experience, the ergonomics are great, and there's incredible satisfaction in building your own desktop environment from the ground up.
I don't know about interesting, I think Niri from the parent looks like something I'd like to try.
I've used i3 and moved to hyprland (because it's pretty).
From the perspective I was coming from, I don't think it matters that much, you'll run into the same issues with any of them.
It's about understanding all the things Gnome/KDE/Xfce etc do for you, and how you can set that up differently yourself using components of your choice.
wmii[0], it implements the acme window layout. But the interesting part is that it exposes its state as a file-system. The main loop is a shell script[1]. So BYO posible, fe here is a Ruby one [2]
I don't know if it's really made me any more productive, but it's a fantastic learning experience, the ergonomics are great, and there's incredible satisfaction in building your own desktop environment from the ground up.