Yeah, aside from GNOME/KDE trying to do a smooth transition, it's kind of a breaking point for everything. We now have Sway as an i3 successor, for example. There are similar projects for other popular window managers, but from what I understand none of them are in a very usable state the way Sway is. This[0] page can serve as an informal list of all the Wayland compositors succeeding old window managers. Waybox is likely relevant to your interests.

[0] https://github.com/swaywm/wlroots/wiki/Projects-which-use-wl...