Applying patches or updates in Viya 4 means updating the image versions to a newer version. Doing so can trigger bootstrapping that updates data stored in PVCs, so to revert a patch or update you would need to apply the prior site.yaml and restore the PVCs to a backup taken from before the update.
-- Greg Wootton | Principal Systems Technical Support Engineer
"Best Practices for Updating Software" in the Viya 4 Platform Administration documentation talks about the rules about restoring from a Viya backup after updating to a new version (eg from 2023.01 to 2023.02). However, currently the documentation does not discuss restoring after a patch update within a version, so I recommend opening a track with Technical Support to get a definitive answer.