Indeed. However it's necessary to use that command on both the main PID and all its child processes, otherwise you will run into issues like the game video stopping but the game logic still running in the background.
This is just a tool to automate finding the pid (via hyprctl or other ways) and correctly suspending it.
There is Nyrna, but it doesn't work on Wayland.
Afaik saving to swap isn't possible as it's something managed by the kernel, although you can try tweaking cgroups. Nyrna also mentions that this isn't currently possible.
I'm not familiar with qtile, but I'm fairly sure there's currently no way to get information about the active window on mutter unfortunately.
Thing with wayland is, each compositor has to implement things their own way, so you're limited to what your compositor allows you to do.
For instance, you can get window information in sway with swaymsg. On other compositors you may have to find workarounds.
No, it uses hyprctl to get the pid of the current active window. Which compositor are you using? It might be possible to get the pid in a different way.
Haha, yes! Ctrl+Z sends a TSPT signal to a terminal process, while this script sends a STOP signal to every process in a game's process tree. Both get resumed with a SIGCONT so they're kinda similar.
Wow, I wish I knew this workaround during my early gameplay lol.