Thank you for posting this in Microsoft Q&A.
I understand your concern about the general availability of the Custom OIDC provider in Entra External ID.
The Custom OpenID Connect external identity provider feature is expected to be available this year. However, we are currently unable to provide a specific release date.
I suggest regularly checking this page for monthly updates on external tenants.
Hope this helps. Do let us know if you any further queries.
Thanks,
Navya.
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