A question came up the other day regarding installing ESU licenses on a shared platform if the service provider (under a SPLA agreement) is licensed for Windows Datacenter but installed Windows STD VM. That’s pretty common and though I would address it today.
One should not be confused over what is installed v what is actually licensed. As the SPLA Provider is licensed for Windows Server Datacenter, the server should be covered with ESU Datacenter. Running a Windows Standard VM when licensed for Windows Server Datacenter does not change the license requirement.
It is also important to note that ESU is not available in SPLA, but is available through CSP, EA, and SCE agreements. The Service Provider will not be licensing ESU, but the end customer. Think of it as license mobility without the need for Software Assurance.
I would recommend checking out the Product Terms page 93. https://www.microsoft.com/en-us/licensing/product-licensing/products
SPLA Licensing 
Jelmer
February 28, 2024 at 6:51 am
This statement seems outdated. https://learn.microsoft.com/en-us/azure/azure-arc/servers/license-extended-security-updates#virtual-core-licensing
Virtual core licensing
If you choose to license based on virtual cores, the licensing requires a minimum of eight virtual cores per Virtual Machine. There are two main scenarios where this model is advisable:
An additional scenario (scenario 1, below) is a candidate for VM/Virtual core licensing when the WS2012 VMs are running on a newer Windows Server host (that is, Windows Server 2016 or later).
With vCore licening you should use Standard edition according to the documentation:
Important
Virtual core licensing can’t be used on physical servers. When creating a license with virtual cores, always select the standard edition instead of datacenter, even if the operating system is datacenter edition.