Doing a little kludge to the script worked around this issue. Until Rocky fixes openssl-libs, we can just exclude it in the distro-sync and leave it with the stock RHEL version for a while.
--- migrate2rocky9.sh.ORIG 2024-07-31 13:38:02.764114561 -0700
+++ migrate2rocky9.sh 2024-07-31 13:40:04.334335470 -0700
@@ -1100,7 +1100,7 @@
fi
infomsg $'\nSyncing packages\n\n'
- dnf -y --allowerasing distro-sync ||
+ dnf -y --allowerasing distro-sync -x openssl-libs ||
exit_message "Error during distro-sync."
# Disable Stream repos.