The kernel command line is applicable regardless of the boot loader used. I have not used refind so do not know what interactions there are.
The fact that the kernel is up to date but the matching kmod-nvidia-NNN package is not there is probably part of the problem.
Try reinstalling all nvidia packages with sudo dnf reinstall \*nvidia\*
After that completes then try rebuilding the kernel mods with sudo kmods --force --rebuild and check that the driver is properly built for the installed kernel. That should properly complete and give an OK then a reboot should load the driver.
If you actually had to add the blacklist lines to the /etc/kernel/cmdline file then it would appear that for some reason the command line was not properly updated with the driver installation.
You can ensure that everything is properly updated with those options by running
sudo grubby --args="rd.driver.blacklist=nouveau modprobe.blacklist=nouveau" --update-kernel=ALL I know it updates /boot/grub2/grub.cfg, /etc/kernel/cmdline, and /etc/default/grub as well as the .conf files under /boot/loader/entries. I am unsure how that translates to booting with refind, but the kernel cmdline should still work for that along with the entries in the .conf files…
It is possible that kmods is not properly completing since grub is not being used so watch the output when running the kmods command to see if it reports an error.