This will require a paid stream to be added to rhcos.json per https://issues.redhat.com/browse/MCO-1672?focusedId=27560148&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-27560148 

There are three tiers of paid marketplace images OCP, OPP, & OKE, and futher there are gen1/gen2 variants for each. This card will involve adding support for updating these paid streams. For these cases, the type within the Image object field should be set to MarketplaceWithPlan.

    # For OCP
    compute:
    - name: worker
      platform:
        azure:
          osImage:
            publisher: redhat
            offer: rh-ocp-worker
            sku: rh-ocp-worker
            version: 4.8.2021122100

    # For OPP
    compute:
    - name: worker
      platform:
        azure:
          osImage:
            publisher: redhat
            offer: rh-opp-worker
            sku: rh-opp-worker
            version: 4.8.2021122100

    # For OKE
    compute:
    - name: worker
      platform:
        azure:
          osImage:
            publisher: redhat
            offer: rh-oke-worker
            sku: rh-oke-worker
            version: 4.8.2021122100 

For hyperGenV1 variants, the SKU value will be appended by -gen1. These do not seem to have ARM variants.

Useful reading on how installations for these clusters work: https://access.redhat.com/articles/6484031

Update: There also appears to be EMEA region specific streams for these too:

https://github.com/coreos/stream-metadata-go/blob/main/stream/rhcos/rhcos.go#L62-L77 

The key differentiation seems to be the publisher(redhat-limited instead of redhat) from the NA region per this thread: https://github.com/openshift/installer/pull/9329#discussion_r2260332642