Want Itunes only showing music i downloaded to transfer to iphone

hi - on my PC i have itunes.

i have downlaoded specific music / playlists that i then want to update those on my iphone.

That's it. All i want to do.

However... whenever i sync my itunes, playlists get duplicated with various songs missing (different cloud markers showing, music shaded out that can't be played etc).

I have turned off sync library on my apple music app.

what i am i doing wrong and what do i need to do perform what i think is a simple data transfer task?

TIA.