Browsing around, that mirror does have the needed file, but under a different path:
/almalinux/8.10/BaseOS/x86_64/os/repodata/repomd.xml (note the insertion of /almalinux/).
I assume you mean something like “dnf clean all” then “dnf makecache”?
I just did that on the affected systems; the problem still occurs as described above.
Those look correct. But the dnf-makecache.service seemed to be holding onto old info?
Today the number of service errors is much less than previous days, so maybe clearing the cache did help but not immediately? (There were over a dozen VMs exihibiting this, I did the cache clean on all of them yesterday.)