User of Manjaro gnome here.
When trying to use the gestures app, the xdotool commands that I configured were not working.
So I have gone to search for a solution.
Apparently, libinput-gestures requires the user to be added in the input group.
So after using the next command, and a reboot it started to work properly:
sudo gpasswd -a user input
Maybe a more permanent solution could be to add the user to the input group at the installation, so that an app that comes with the OS would work out of the box.