Synchronizing the library between devices is a long standing request. There are lots of threads requesting it, just do a search. Here are a couple of the more prominent ones:
If the source of these playlists and music is a streaming service like Apple Music Streaming, simply select the source in the djay library, touch or click onscreen and drag down to perform a refresh.
Hello! It’s been more than 10 days since my last reply. I’m going to consider this topic completed for now so I can focus on others. However, please feel free to respond and we can definitely revisit this. Thanks!