jenkins-maven-cd-action should have an option to mark the new release as pre-release (while still taking it out of draft status as today); and the UC generator should automatically limit a plugin version to the experimental UC when it can find an associated GH release and that release is marked as pre-release.
https://groups.google.com/g/jenkinsci-dev/c/Tx46XXL15l4/m/KvruHP2BAgAJ