The process of building custom solutions for SharePoint Server.
Please note that this is a user support forum, not Microsoft Support. Forum members do not have access to your organization’s licensing agreements, Volume Licensing entitlements, product keys, or backend systems, so I cannot provision an SPSE license or make an ISO available for your account.
Based on the information provided, this appears to be a licensing availability issue rather than an activation issue.
Since the licenses have already been procured under Open Value, the availability of the corresponding SharePoint Server installation media, product key, and download entitlement would need to be verified through the appropriate Microsoft Volume Licensing support channel or your Microsoft licensing partner/distributor.
It is also important to distinguish between license entitlement and the availability of the installation ISO/download in the licensing portal. The fact that the ISO is currently unavailable does not by itself establish that the licenses were purchased incorrectly. The actual entitlement associated with the agreement would need to be verified first.
In fact, Microsoft currently provides the SharePoint Server Subscription Edition (SPSE) installation ISO through the Microsoft Download Center. However, installation as a licensed product requires the appropriate product key.
I recommend contacting your licensing partner/distributor or Microsoft licensing support and providing the relevant license detail, the coverage period, and explaining that the missing installation media is currently blocking the customer’s planned deployment. They should be able to review the actual licensing agreement, verify whether the purchased licenses provide the required SharePoint Server Subscription Edition (SPSE) entitlement, and advise how the appropriate product key can be obtained.