Trying to connect more than 1 Xbox one S controller via Bluetooth

Try doing this in the Arch Wiki
https://wiki.archlinux.org/index.php/Gamepad#Xbox_Wireless_Controller_/_Xbox_One_Wireless_Controller

Use either:

echo 1 > /sys/module/bluetooth/parameters/disable_ertm

Or add this file to your module configuration:

/etc/modprobe.d/xbox_bt.conf

options bluetooth disable_ertm=1