RetroPie doesn't use the desktop env (which I think you'd need for VNC) and it doesn't have it installed by default if you use the provided image. While some Pi4 users run EmulationStation from the desktop, it's not a supported or tested configuration and you may bump into problems at some point.
Contributions to the project are always appreciated, so if you would like to support us with a donation you can do so here.
Hosting provided by Mythic-Beasts. See the Hosting Information page for more information.