Frank Cox:
Here's an idea, though I don't know if it would be practical.
I assume that at some point everything that goes into RHEL and its "official" updates travels through the Stream ecosystem beforehand.
So what about the idea of maintaining (somewhere) a list of official updates to RHEL as they are released, and then have some kind of a dnf enhancement or script that reads that list and updates a local Centos installation using only the rpms on the list and ignoring everything else. Stuff that's released to Stream would be downloaded and installed at the point where it has been released for RHEL and not before.
That would (I think) keep your Centos installation in sync with RHEL.
That (if it worked) would only work up until the stream reaches EOL at the end of 'Full Support mode '- which for EL 8 is 31st May 2024 (not as we were expecting, sometime in 2029)
Or even better, as Redhat appear to be taking full control of 'CentOS', why don't they just make RHEL available to all for 'free', and you just pay for support if you need it - i.e. a bit like it is now, RHEL if you pay, CentOS if you don't - I'm sure that would make everyone happy :-)
James Pearson