I hope you´re doing well today. Could you please advise if you´re still having this issue?
It looks like the directory where the custom PostgreSQL installation should be present is not found or cannot be accessed?
"qdc_pg.service: Failed at step EXEC spawning /usr/pgsql/qdc11-15/bin/postmaster: No such file or directory"
Have you verified the permissions on the directory and confirm that these are either "postgres:postgres" or "qdc:qdc" ?
If the permissions look correct and the issue persists, then you are kindly invited to raise a support case with the corresponding screenshots detailing the issue and we´ll gladly assist.