You can try this Repo after a fresh Installation without Updates:
https://download.opensuse.org/repositories/home:/Sauerland:/hardware/openSUSE_Leap_15.1/
or this for an updated openSUSE Leap 15.1:
https://download.opensuse.org/repositories/home:/Sauerland:/hardware/openSUSE_Leap_15.1_Update/
This last Repo will automatically get the newest kernel-module-packages, if Leap 15.1 will get a newer kernel version.
Name of the package is:
rtl8821cu-kmp-default
Source of the package is from https://github.com/brektrou/rtl8821CU
/sbin/modprobe -c | grep -i "0bda.*c811"
alias usb:v0BDApC811d*dc*dsc*dp*icFFiscFFipFFin* 8821cu