xwayland: Disable the MIT-SCREEN-SAVER extension
Xwayland is just a Wayland client, no X11 screensaver should be expected to work reliably on Xwayland when running rootless because Xwayland cannot grab the input devices so it has no way to actually lock the screen managed by the Wayland compositor.
Turn off the screensaver on Xwayland when running rootless by setting the screensaver timeout and interval and their default values to zero and disable the MIT-SCREEN-SAVER extension.
Using the standard command line option "+extension MIT-SCREEN-SAVER"
can re-enable it at runtime, if ever needed.