how do i take back control of my music in itunes

As you hopefully realize, Apple Music and having an iTunes music collection don’t blend well at all. They use completely contradicting methods for accessing music.

If you intend not to use Apple Music, then turn off iCloud Music Library.

As you probably realize, MacOS High Sierra is now four years old, so things were done somewhat differently back then.

Anyway, since you likely realize from the above discussion there is a strong connection between Apple Music and iCloud Music Library, you should likely start by turning on “Show Apple Music Features” as displayed in your screenshot.

Turn it off here.

You have asked us to guess what steps you performed to lose that control.

How, exactly, have you "lost control"?