Not sure if many people are aware of this, but somebody is working on a VNC server for OpenStep:
https://github.com/gcasa/NXVNCServer
It's been mentioned in passing in the Discord server.
@turbolent has applied (https://github.com/gcasa/NXVNCServer/pull/1) his knowledge of the private Interceptor Framework (https://github.com/turbolent/openstep-interceptor-example) that OPENSTEP has for low-level graphics access and is awaiting a PR merge. The hard part is getting gcasa's attention!
I really need to look into this. I really want a working VNC server