After # mokutil --import /var/lib/dkms/mok.der

[dragonserw@fedora rtl8821CU]$ sudo sh ./dkms-install.sh
About to run dkms install steps...
Creating symlink /var/lib/dkms/rtl8821CU/5.4.1/source -> /usr/src/rtl8821CU-5.4.1
Sign command: /lib/modules/5.19.9-200.fc36.x86_64/build/scripts/sign-file
Signing key: /var/lib/dkms/mok.key
Public certificate (MOK): /var/lib/dkms/mok.pub
Certificate or key are missing, generating self signed certificate for MOK...

Building module:
Cleaning build area...
'make' KVER=5.19.9-200.fc36.x86_64...............................................................
Signing module /var/lib/dkms/rtl8821CU/5.4.1/build/8821cu.ko
Cleaning build area...

8821cu.ko.xz:
Running module version sanity check.
 - Original module
   - No original module exists within this kernel
 - Installation
   - Installing to /lib/modules/5.19.9-200.fc36.x86_64/extra/
depmod.......
Finished running dkms install steps.
[dragonserw@fedora rtl8821CU]$ sudo modprobe 8821cu
modprobe: ERROR: could not insert '8821cu': Key was rejected by service
[dragonserw@fedora rtl8821CU]$