When I open Lr on the MBP it shows the previews from the old Lr Classic library (under a separate Adobe license). Yes, I logged out of the old account and into the new. I tell it to open the new .lrcat and also set that as the default catalog.
That means you either moved the wrong catalog, or you haven't opened the catalog you moved.
The catalog and previews are local - e.g. not related to a specific Adobe account. The only exception is photos stored in the cloud, perhaps from mobile, which may sync down from the cloud if it asked you to change to syncing this catalog.
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