So after reciving my own steam controller (i hate this input thingy right now, but its gettin better) i've found out that we do something strange in manjaro for all the time
our udef rules for the controller input are set to uaccess for uinput (because be default /dev/uinput is only read/writable for root) thanks to uaccess its also read/writable for the user that is logged in.
So the big "BUT?!" is that we dont even load uinput at boot time. So i've tried 2 days whats wrong and why my user dont have access to /dev/uinput, but thats was the simple solution
getfacl: Entferne führende '/' von absoluten Pfadnamen
# file: dev/uinput
# owner: root
# group: root
and the steam controller even works without steam.
So i've added this to my steam-manjaro re-do
so if you're using a steam controller just do this for the normal manjaro pkg
echo 'uinput' | sudo tee --append /etc/modules-load.d/steam-uinput2.conf
sudo modprobe uinput
this will add the module to load on boot AND loads the module also now