It looks like mainly a Hyprland fix (and maybe some wlroots based compositors). The old method still works with sway for me, and there's a another approach using a virtual edid that should work everywhere, but perhaps not with Nvidia cards (see here: https://discuss.kde.org/t/how-to-create-a-virtual-monitor-display/2725/5).
I'm not sure if Plasma or Gnome have any support for headless monitors outside of the EDID method.
This is a much more active fork, called Apollo, which got headless mode, along with many, many more useful features, a long time ago. Artemis (moonlight) client also supports clipboard sync
Apollo only works on a windows based server at this point. I like Apollo a lot, but I only have a Linux server available that I can put a headless install on (in an unprivileged lxc actually).
Last time I looked into Apollo it had a bunch of controversy around it and it's owner. And it was extremely hostile to anyone seeking help in their discord support channel.