I use Wayfire [0], a customizable compositor based on wlroots, the same base as sway. It's quite involved and not absolutely perfect yet, but it has some features I haven't yet seen on other DEs like being able to swipe horizontally on your touchpad to smoothly switch workspaces (following your fingers) and the satisfaction of having it properly configured is pretty high.
There have been 3 issues I've had regarding it, 2 I'd call minor:
- I haven't found a way to rearrange external displays, though it is theoretically supported
- After a bug in my TV switching to the lowest possible resolution through switching the input in home assistant it would not work with 4K again until after a complete reboot (so it may not even be a wlroots issue)
- XWayland apps are unresponsive in the upper half of the second screen (4K at 1x scaling)
Using mostly native Wayland apps neither of these have been deal breakers for me. Something under-discussed is that virtual desktops are per-screen, which I find quite cool.
So that's my adventure with Wayfire, but I would assume that Gnome and KDE have perfected multi-screen usage on and off of Wayland by now.
Wayfire's developer here, have you looked into output configuration on our wiki?
Also, is there a chance your 4K screen has negative coordinates? It is well known that Xwayland does not react if an output has negative coordinates (or at least partly negative coordinates).
There have been 3 issues I've had regarding it, 2 I'd call minor:
- I haven't found a way to rearrange external displays, though it is theoretically supported
- After a bug in my TV switching to the lowest possible resolution through switching the input in home assistant it would not work with 4K again until after a complete reboot (so it may not even be a wlroots issue)
- XWayland apps are unresponsive in the upper half of the second screen (4K at 1x scaling)
Using mostly native Wayland apps neither of these have been deal breakers for me. Something under-discussed is that virtual desktops are per-screen, which I find quite cool.
So that's my adventure with Wayfire, but I would assume that Gnome and KDE have perfected multi-screen usage on and off of Wayland by now.
[0]: https://wayfire.org/