Comment by serbuvlad

There is an xdg-desktop-portal which an application can use to register a global shortcut.

https://github.com/flatpak/xdg-desktop-portal/blob/main/data...

Not sure which compositor support this and which ones don't. Hyprland, which I use, supports it.

There is also ydotool, which can emit key presses anywhere in Linux by registering a virtual uinput device.

https://github.com/ReimuNotMoe/ydotool

Using these two building blocks, it should not be very difficult to implement an application that implements global macro support.