I can't use CentOS Stream - it is beta quality and has critical bugs. For example: https://bugzilla.redhat.com/show_bug.cgi?id=1913806 This bug is critical for me, because I use systemd-nspawn containers for production. I will continue to use CentOS Stream in the future, but only as the beta-tester, to see what new will be in the future minor release of Oracle Linux / Alma Linux / Rocky Linux.
What you are facing is a typical issue of moving things forward and just because something worked in the past doesn't mean it will always work in the future. This is why you are testing and this is why Red Hat is testing their supported use cases.
If you have a RHEL subscription and Red Hat says they are supporting systemd-nspwan containers, they would very likely test it and thus the regression would already have been detected. Red Hat always says they per se don't support something that is not tested.
But what are your options now, if it is not supported and thus not tested and hence won't work in RHEL 8.4 and thus not in CentOS 8.4, nor OL 8.4, nor Alma or Rocky 8.4 (since they all inherit the bugs from RHEL). Where would you open a bug report and hope to get it fixed (for free)?
If you have a RHEL subscription you could open a support case and likely have more weight to get it fixed.
If you are Streams User, you can early detect that something *you* depend on is not covered by Red Hat's test suite (maybe because it is not - yet ? - supported by Red Hat), open a bug report in Red Hat's bugzilla (as you did) and thus it is way more likely to get some attention than in a OEL, Rocky or Alma bug tracker where none of the RHEL engineers is looking at (why should they?).
If you are on OL, Alma or Rocky and you are facing the bug when updating to 8.4 (still assuming since Red Hat is not supporting it and thus they don't test it and thus won't detect it before you do), what would be your options? How would you get it fixed? What would you do until it is fixed in 8.5 or 8.6? And the same thing you would there, you can also do for Stream. So I don't see much value in moving to these rebuilds, except that you get exposed to bugs much later, bugs that will likely not be fixed, as it's a regression in a unsupported feature.
And if Red Hat would not have done the strategic decision to move to Stream, you would be exactly in the same situation with CentOS Linux as you will in the future with Alma, Rocky and Oracle.
So since nobody yet showed that Red Hat is supporting systemd-nspwan containers and thus it is indeed a regression they should really not put into Stream, I would refuse to follow your logic of calling Stream Beta due to a regression for a use case that was never supported.
However, having you using Stream and reporting regression in unsupported features might in the end make Stream, RHEL and all their rebuilds much better supported.
Thus I think it's a good thing and it's also good you are reporting these things.
And as a Stream user and contributor you can also add your use case to t_functional which in the end becomes gating for Stream. So you avoid future regression for your use case, although it is even not officially supported.
But calling Stream Beta just because of a regression in a unsupported future?
~pete