(On a discussion as to why Wayland has no mechanism to define a primary monitor)
Actually fucking delusional.
That setting is specific to KDE's environment. I don't think non-KDE apps have a standard way to figure out which monitor is the primary (for things like status bars and docks).
Note the first point. Some compositors don't have that concept, but that means that some compositors will. Because of practical considerations. Now you have an off-standard feature that users want, but it's entirely dependent on how the authors of the compositors implemented it. Have fun creating programs for this kind of schizo environment.
This is the biggest fucking issue. People can bitch about the underlying structure of X11 all day long, but from the application development perspective, you had a solid separation of the display server, the window manager and the actual applications. You could run a single application that took up the whole screen without a window manager.
Combining the window manager and composer was like the fucking Itanium. Let's just build scheduling into the compiler, that way when we come up with better scheduling algorithms, we just update the compiler! Yea, great. Except both of those things are insanely complex and difficult. CPU architects write scheduling in their own tools which are totally different than what compiler authors are use to and visa-versa. Now the compiler author has to think, "Okay, I told instruction batch 1 to divide, now I can't send it another division command for five cycles and that's when I can read the result." EPIC wasn't even a pure implementation of VLIW, and it was still retarded.
Not having a standard fucking way to do something across all environments is insane. Tiling window managers in X11 can use an x window property to know if some windows should be dialogs. Wayland has no such attribute at all. This meant on Sway, the file transfer dialog in Dolphin file manager was treated like a full window instead of floating. You needed custom regex rules on the title just to make sure the file transfer dialog didn't split your windows. This isn't an issue with Hyprland and I'm not quite sure how they worked around it.
Wayland reduces the overall number of possibilities. Building new managers was a task in and of itself. Now you have to build it with a composer?! Why not just have it do one thing and not have to debug endless shit in wlroots, aquamarine or whatever the fuck you're using? It's core design makes it more difficult to write complex applications that work across every different composer. Trivial applications like chat and Gimp are fine, but clipboard managers, screenshot tools, recorders, workspace managers, KiCad .. they all have to support each individual environment or portal APIs that may or may not exist (XMPP component vibes here).
It was a shit decision and the core Wayland devs have never acknowledged what a fucking terrible idea this was. I hope XLibre gets HDR support, patches mpv for Xlibre+BT.2020 and years from now we're seeing Gtk and Qt reattach XLibre support because it works better than the Wayland dumpster fire.