Which cloud to choose for virtual desktops?

Question

Freelance

Hello,
There is a task for different users to organize a controlled environment for remote work, something like a virtual desktop.
The reason is the need for greater control over the work process, the ability to share a connection to the desktop for explanations and discussions, the ability to set up the correct working environment for the user in advance (conditionally one machine - one project) and, importantly, quickly reconnect different users to different virtual machines with different projects (machine communication with each other is not required).
Also, the nuance is that not all data makes sense to trust users, for example, passwords to a certain mail, but it is convenient to go into it yourself and connect them to a virtual machine for further work. In these cases, I still connect remotely to my computer, but this is not at all convenient.
Regarding the operating system: users usually sit on Windows, but given the irrationality of buying licenses, I see the point in organizing the process on the same Ubuntu.
Can you tell me what can be used for this? I’m looking at digitalocean.com for some 1Gb RAM tariffs (well, or more according to the situation + there is a traffic limit, but I don’t imagine its real consumption yet), will it be suitable for my tasks?
Can you advise something else, some kind of mega-scheme with virtual secure auto-synchronizing machines on users' computers? :-)
Thank you in advance for your attention!