NoMachine software lets you access your remote computer whether it’s Windows, Linux or Mac. You can install it on the physical machine or on a VM. You can install it on your Windows VM already running on your Linux server (you will need a hypervisor to do that), and you will be able to get remote access to that Windows VM.
If you choose one of the products with the terminal server functionality (for Linux) you can run multiple instances of the Linux desktop on the same host.
I suggest you check out the following:
What can I do with NoMachine? https://www.nomachine.com/AR10K00716
What do I need to use NoMachine? https://www.nomachine.com/AR10K00723
How to get started with NoMachine – https://www.nomachine.com/getting-started-with-nomachine