How can I stop songs from automatically redownloading after deletion on my iPhone?

I have many songs in my library, most downloaded. I’m in the process of freeing up storage by deleting the downloads of certain songs. They are still in my library and playlists, just removing the download, but no matter how many times i delete the download they always are redownloaded a couple days later. I have sync library on, optimize storage on at 32 gb, and automatic downloads off. I do have a MacBook Air with my music on it as well.

[Re-Titled by Moderator]

Original Title: Why do songs redownload after deleting the download?