In case you are coming from Ubuntu and wondering why there is no fractional scaling option on Manjaro Gnome with Xorg, well here is the answer.
Fractional scaling on Gnome - Xorg is not supported by the project, they do officially support that functionality only on Wayland.
However, Ubuntu has patched some Gnome components to make it work on Xorg and thanks to their effort, these patched packages are also available on Manjaro.
Before installing please keep in mind that fractional scaling on Xorg is a experimental feature!
Simply install mutter-x11-scaling and gnome-control-center-x11-scaling from the repository and reboot.
After that you will find a toggle option in the Display settings to enable fractional scaling and per monitor scaling on Xorg.
More information can be found on Github.
Outdated Information about unavailable gnome-control-center-x11-scaling
gnome-control-center-x11-scaling is currently not available for GNOME 42, because Ubuntu is using version 41 for their current LTS and the patches have not been ported.
You can still use mutter-x11-scaling but will have to enable/disable fractional scaling via gsettings.
To enable fractional scaling after installation run:
gsettings set org.gnome.mutter experimental-features "['x11-randr-fractional-scaling']"
To disable fractional scaling run:
gsettings reset org.gnome.mutter experimental-features
With GNOME 42.2 gnome-control-center-x11-scaling is available again.