Please help me understand your comment that "We do rootless containers different then redhat way". Red Hat is the leading contributor to podman and its infrastructure libraries, and AFAIK podman was the first container engine to do rootless. What Red Hat does different than others, and which others?
Rootless containers is not just about podman. It also requires proper kernel support for uid namespaces, many filesystem uid and gid mapping tricks, and also network level features so a container can do networking without root not extended kernel capabilities. So while a podman release available during RHEL8.0/8.1 (don't remember exactly which release of podman and RHEL) was already capable of rootless, other components were not there so there were restrictions running some operations on rootless mode, that's the reason it was not supported.
Beware that, when talking about RHEL, "supported" has a very strict meaning that customers can expect it to work in a multitude of use cases and get responses to support tickets within a contractual SLA. So many features that "just work" and are declared as "supported" by upstream projects and Linux distros such as Fedora, are not "supported" in RHEL because they are not considered prime for production-level usage within the contractual SLA.
