Is there a window manager that does not rely on existing X/Wayland installation?

Several days ago I was fine-tuning my keyboard layout and messed up xkb files in a way that the entire xserver didn’t boot up. I had to troubleshoot the issue with a tty terminal. It took a long time.

It occurred to me that I would handle the issue way faster if I would have an access to an even basic GUI window manager (TWM’s feature set would be enough). It occured to me that maybe it is possible to pack all necessary Xorg files into a single executable and use it as a fallback WM to run with no GUI dependencies when xserver falis for some reason.

Does it exist?

Your GUI low level is a choice of 2 only, X11 or Wayland.

You can use linux console to recover, but its command line not gui.

I do not mind usage of technology behind Xorg or Wayland, but is there a manager that keeps all necessary parts of their code in it’s own executable/cataloge to run in case of a fatal xserver error (if something is wrong with standard Xorg/Wayland installation or their configuration files)?

In this case you edited a config of X11 not the window manager config.
Changing window manager does not help.

When I break my systems in this sort of way I use a terminal console or via ssh from another systems to debug and fix.

One debug method I have used is to create a new user and login as that new user. Then I compare config for a fresh login with an main user’s config files.

But you know what caused the breakage so a console would seem to be the easy way to fix from the command line.

Do you know about the Alt-Ctrl-F3 to get a login on the console?