Red Hat does not offer any support for CentOS Linux or CentOS Stream. Though I saw some announcements that other companies were. I didn't read enough to establish what level of 'support' they were offering was.
Red Hat offers Extended Lifecycle Support (ELS) add-on subscriptions for RHEL 7.9
One could convert2rhel CentOS Linux 7, then add on ELS subs. Or you could convert2rhel your CentOS Linux 8 systems, then they'd be RHEL8 which is still in it's standard lifecycle. Red Hat doesn't offer conversions from CentOS Stream 8, but maybe that will happen. I know the team that manages convert2rhel has had some successful conversions now that CentOS Stream 8 is no longer running ahead of RHEL8. But it's still not a 'supported' conversion so if it breaks, you would get to keep all the pieces.
