The issue in this case is post successful connection to RHEL 9, the password does not seem to be Transparently injected. The user is prompted to provide the Password.
We can see in the ssh_proxy logs that PAM is waiting for something to complete the password injection
Release : up to 4.1
A patch or update to the PAM versions 4.1.3 and below is required for this to work since modifications to the PAM code are required for RHEL 9