Licensing OS Windows sandboxes as virtual systems under QEMU?

Question

Virtualization

Greetings!
We have the entire set of sandboxes running on our server, starting with XP SP0 and ending with the latest 10.
Moreover, we can launch and work immediately with a dozen Windows 7, which are based on the same initial disk and differ in snapshots.
How is this licensed? No way? Whereas products like:
https://www.hybrid-analysis.com/
https://joesecurity.org/
https://malwr.com/
are licensed as well as heaps of other public sandboxes, how do they live?
ps in microsoft they said they don't know, but distributors - it's impossible

Answer 1

Purchase a corporate Open License / Value License for Windows 10 Pro for the maximum number of concurrent systems. There will be one serial number for everyone, the right to downgrade, EMNIP, allows you to use it starting with Windown XP Pro, only you must have your own license numbers and media, at least one for each version of the system.
If you provide access to virtual machines to unauthorized persons, then you also need to become a Microsoft partner and conclude a Service Partner License Agreement (SPLA).
PS Amendment - SPLA is necessary for server systems. For desktops:
Customers who subscribe to desktops through third-party hosting providers will need to pay Microsoft a Windows VDA license for each device that accesses a Windows client virtual machine in the datacenter. In addition, hosting providers must guarantee the isolation of equipment and other resources for each company (that is, no two companies should be able to share a set of resources such as equipment, storage, and the like).

Answer 2

How is this licensed? No way?

Why? Buy a corporate license, and that's it.

Whereas products such as

And it is better to ask the owners of these products, who knows how they licensed and whether they licensed at all.

Microsoft said they don't know

Lie. They cannot but know, because it is they who actually distribute licenses, they simply do not want to.