As @sterzy said this has nothing to do with Proxmox. In general, what you are trying to do is not supported. These are the google keywords that will help you learn more "windows 10 multiple users simultaneously rdp".My intent is to create a virtual machine with WIN10 on PROXMOX that can then be shared simultaneously by multiple authorized users
Its one solution. There are many others, ie VDI, Terminal Server, etc.So that, if I suppose that 5 clients need to share a same virtual machine, the only solution is to clone 5 times the virtual machine, it's right?
Sure. Both approaches are outside of Proxmox "installation and configuration". But there are many articles online: https://www.parallels.com/blogs/ras/vdi-thin-client/is it possible to run from the initial BOOT of the THIN CLIENT the virtual machine located on the PROXMOX server?
If the users are just going to use the browser then you can always drop Windows 10 and use a Linux desktop VM. That should allow multiple users.
Any suggestions on a tutorial for my requirement, which is to create a single virtual machine to be shared by multiple PCs simultaneously and independently?