Sync problems AGAIN like everytime please help and fix

I swear to the techno Gods and all the others EVERYTIME I use the sync there is problems. I will spare the details of last problems (many) and get to the current and hopefully someone can help. it really very simple what I am trying to do and it just wont work. I hope one day I can do a sync and not have to get on this community for help. PLEASE

But I do appreciate the help I have had and hope someone can help again (pretty please)

Problem Sync from Denon prime 4 controller hardrive does not sync to engine prime software on computer

the basics -full library stored on computer hardrive and is synced to controller hard drive -both controller and software are uptodate -i play around on controller make new playlist on controller, add songs to said playlist. Cool all is well. -I want to load up said playlist onto an external and play at friends house -conect controller to computer hit sync, sync from controller to prime -everything looks good playlist visible on both drives

The bad as soon as i disconnect the controller drive the playlist that i “synced” to computer are gone. and now if i try again the option the sync from controller is not even visible. it says something like no new items to sync. what weid is whil the controller is connected i see the playlis in prime (on computer) but the moment i disconnect i dont.

what am i missing

and can this please be simpler…ie actually work