It would be nice to get Steinberg’s official stance on this, but here’s my take:
VST Cloud: umbrella marketing term covering VST Connect, VST Transit and VST Join
VST Connect: great product, really took off during covid and being actively developed; think of it as enabling recording in true studio style, where you’re at the mixing console (Cubase) and the artist is in the (acoustic) studio, except that space can now be anywhere with a decent internet connection. The artist does not need to have Cubase, and the remote client is a free download (after registration).
VST Transit: aimed at non-realtime collaboration, whereby Cubase users can collaborate on projects. Think of it like OneDrive, but built in to Cubase, and collaborators all need to have Cubase.
VST Join: also intended for non-realtime collaboration, but appears to be in permanent beta and doesn’t seem to have been further developed, which is a pity because it enables one Cubase user to manage a project with contributions from others remotely, and does not require all others to have Cubase (the “client” is a free download, after registration).
I could be wrong of course, but I’m happy to be corrected by someone from Steinberg showing us their roadmap for these products!