This topic may address the issue: Downgrading kernel on Silverblue - #3 by jlh
You may simply be able to install additional overrides to resolve the issue.
I’m seeing the actual issue as
Problem: package kernel-6.4.9-200.fc38.x86_64 from @commandline requires kernel-core-uname-r = 6.4.9-200.fc38.x86_64, but none of the providers can be installed