You can fix that by adding the following entries at the end of your /boot/cmdline.txt file:
cgroup_enable=memory cgroup_memory=1
It is really a docker issue related to cgroup capabilities. Reboot and you will be good to go.
However, if you are planning to use the latest chromium-docker to have widevine, you are out of luck with the rest of us: chrome://components/ does not list widevine anymore 
And there are a couple of other minor issues. For example, you may need to install inetutils to get hostname to work for that script and, if your paprefs is broken, you will need to install pulseaudio (uninstalling pipewire-pulse first, since it conflicts):
sudo pacman -S inetutils
sudo pacman -S pulseaudio
Anyway, your mileage may vary but this should get you going.
Best regards!