Hello @moment
Thanks for using Cloudera Community. Based on the Post, CM Agent Setup fails with "Unsupported RHEL Release". The same is feasible if the OS used by Customer isn't Compatible or Supported with the Cloudera Manager/CDP Release. Review Support Matrix [1] & ensure the OS used is Compatible based on the Cloudera Manager/CDP Release being used by your Team.
Regards, Smarak
[1] https://supportmatrix.cloudera.com/