I used AutoHotkey to send keystrokes as media commands to an mpv window (if one is open somewhere in the background -- so I don't have to alt-tab from games) and as those literal keystrokes to the rest of the system. On Linux, I do that with `xdotool`. But that's an X11 thing; on Wayland, yeah, there's probably no `xdotool` replacement yet. :p