semantic model Another user operation is already running. Wait for a few minutes, then refresh

According to Microsoft support it is part of a bigger known issue with Direct Lake.

Other symptoms are when you do get the new model created tables that are in lakehouse do not appear for 24 hours and you can only add a few at a time if they do exist. Of you try to add more you get this error again regardless of running pipelines, notebooks etc.

Basically you have to do it bit by bit by bit adding tables over a number of days to build your new direct lake semantic model. Crazy.