I downloaded Sylo synth, the free version, and maybe I’m dense but I don’t see where it supports virtual midi or background audio. Read the help, tutorial and troubleshooting guides on the web site and couldn’t see where either feature is supported. Sylo synth does look cool though and hope that the developer eventually adds those features and AudioBus so we can use it with Cubasis.
Suspect that it will be a long time, probably never, before we can manipulate third party synth app parameters from inside Cubasis like we do with VSTs on desktop Cubase.