Thanks for your message.
Cubasis projects can be imported to Cubase via the freely downloadable Project Importer extension. Its features and limitations are described in the following article: About the Cubasis Importer
Cubasis for iOS and Android and Cubase for Windows and macOS are fully independent app developments, which come with individual features matching the requirements of the individual platforms.
Please choose one of the export options available in Cubase to create STEMs and/or MIDI files, which then can be imported via Cubasis.
We’re constantly monitoring the options to provide an easier solution to load Cubase projects with Cubasis.
Best,
Lars