Hi,
The repodata directory is missing from 13/redhat/rhel-8-aarch64:
# for i in 12 13 14 15 16 17; do echo "Version $i:"; curl -s -o /dev/null -w "%{http_code}" https://download.postgresql.org/pub/repos/yum/$i/redhat/rhel-8-aarch64/repodata ; echo; done
Version 12:
301
Version 13:
404
Version 14:
301
Version 15:
301
Version 16:
301
Version 17:
301