Hello,
In case of BIMcloud Basic, there is no easier way than export and import projects and libraries one by one between the new and old BIMcloud Basic setups.
Migration can work between different BIMcloud Basics with the same build and Archicad lock version, but it's similar to what you can achieve with re-share. Also, while you re-share your projects, it's a great opportunity to do a maintenance and check if each and every project is needed, or some of them can be archived.
Kind regards,
Noémi
Noémi Balogh
Community Expert, Admin