I really wanted to switch to this but unfortunately it doesn't have support for Xwayland scaling :( in case youre using 4k, On Wayland only KDE and Gnome seem to have gotten this working.
If you're on KDE check out Karousel. It's a KDE Kwin script that does this type of scrollable tiling right inside KDE. Works great on my ultrawide monitor.
I think it would be better to say “simplified desktop Linux”. The project is more about the Linux “plumbing” than about opinions about the desktop environment.
Chimera is not even out of beta and it already includes GNOME, KDE, XFCE, LXQT, and others. The founder uses GNOME but Chimera users do not have to.
https://github.com/YaLTeR/niri