Issue is with already published version for ojdk11 (https://access.redhat.com/documentation/en-us/openjdk/11/html/installing_and_using_openjdk_11_on_rhel/installing-openjdk11-on-rhel8) and the same chapter for ojkd8 (OPENJDK-175)

This whole chapter is incorrect. It's promising installation multiple version but doesn't describe it.
It should contains something like this - https://access.redhat.com/solutions/3040171