Here’s a screenshot of SC running Cardinal (a free VCV Rack clone, as a plugin) via VSTPlugin.
This is without patching audio in JACK. Scsynth is the plugin host; all audio is “in the box” in scsynth.
Cardinal: Releases · DISTRHO/Cardinal · GitHub
VSTPlugin: Releases · Pure Data libraries / vstplugin · GitLab
(Note, I’m not affiliated with either project – just obsessed with interoperability.)