The OKD docs show that you can get support from Red Hat, but the OKD is upstream version not supported by Red Hat Support.

Link:
https://docs.okd.io/4.18/support/getting-support.html

"""
From the Customer Portal, you can:

Search or browse through the Red Hat Knowledgebase of articles and solutions relating to Red Hat products.

Submit a support case to Red Hat Support.

Access other product documentation.
"""
    

OKD 4.18 docs
    

    1.
    2.
    3.
    

The OKD docs show that you can get support for upstream project.
    

The OKD docs should not have mention about getting support from RH about upstream project.