Hi, I just found this.
Not sure if tis will be a complete solution for migration with preserved settings or just and import from one library to another.
“Starting with macOS Catalina, Aperture is no longer compatible with macOS. If you upgraded to macOS Catalina before migrating your Aperture library, you can still use Photos to choose your Aperture library, as pictured above. However, Photos might show only the original photos, not any edits that you made to them in Aperture.
Apple will soon release a macOS Catalina update to help resolve this issue. Until then, you should keep your Aperture library and expect to migrate it to Photos again. You may also want to avoid using Photos to add or edit photos, because those changes won’t be kept when you migrate your library again.
This article will be updated as more information becomes available.”