How to create cloud lab similar to Pwnbox?


I am curious how I can run the setup similar to Pwnbox in the cloud.
I have an AWS instance with Kali but what is the best solution for VNC/virtual desktop implementation? My current setup is very slow compare to Pwnbox

There are several options. but first you need to tell us what you are using currently?

Options are like following

xrdp (requires a remote desktop client)
noVNC (web client use your browser) ( web client use your browser )
GitHub - InstantWebP2P/peer-vnc: Secure Access VNC from anywhere ( webclient use your browser)

Thank you very much for the options and links, they are definitely useful.
At the moment I use tightVNC server and VNC Connect client but not very happy about the mix. I will evaluate another possibilities.