Does an Azure Plan support all the same Azure services as a direct subscription?

Yes — an Azure Plan is not a limited or cut-down version of Azure. It provides access to the same services, regions, and features as a subscription purchased directly from Microsoft. The difference is purely commercial (who you're billed by and who provides support), not technical.

If you ever encounter a specific service or feature that seems unavailable, it's more likely tied to subscription type/quota limits (which can affect any subscription) rather than something specific to Azure Plans.