Came across this issue with a RZ03-0203 Gaming Keyboard [BlackWidow Chroma V2] .
After those steps the device wasn’t recognized so used polychromatic throubleshoot and checked the red flags. Was super useful and easy to see the issues I was having and the reasons so, In my case:
$ dkms install -m openrazer-driver/3.1.0
$ sudo pacman -S linux515-headers
Unplug the keyboard, plug it again and restart openrazer-daemon and voila!
I hope that helps some how