Turn off iCloud music library

Please help. I have a collection of over 25,000 songs in my iTunes music library.

My Mac Pro is old and is running High Sierra because a while back I could no loner update.

2 months ago I was able to add/change music playlists on my iPhone -

and now I can no longer do that. When I select the "music" menu for my iPhone in

iTunes I get "iCloud Music Library is On" and can no longer sync.

Thank you and Merry Christmas to all except to the Apple developers

that have made changes to iTunes that have made my life miserable.