Nope, same result. I don’t know what the problem would be because the mouse moves sometimes but resets to the center of the screen on others (because Input.MOUSE_MODE_CAPTURED resets the position to the center of the screen.)
I have tested your MRP and it works for me on Debian X11 Xfce.
So this could be a wayland-related bug.
May I ask you to create a bug report on our bug-tracker GitHub · Where software is built
Thank you. It turns out the issue may have been that the version manager I had been using (Godots) had been forcing it to run under X11 and that may have prevented it from moving the mouse through some permission issues.