I'd like this for LyX as well.

Just to make sure I understand, Red Hat no longer includes texlive as part of RHEL (presumably starting with RHEL 9)?

That is my understanding from the website's RHEL9 package manifest. Unless I'm missing some other weird repo.

On my RHEL9 system I see a lot of texlive package in appstream, just listing one here:

texlive.x86_64                                            9:20200406-26.el9_2                rhel-9-for-x86_64-appstream-rpms

But we are missing biblatex.  Generally with EPEL one requests missing packages be added to the texlive-extension package - which I have done for biblatex here: https://bugzilla.redhat.com/show_bug.cgi?id=2459059