Unless you plan to stream your songs through Apple Music, I like to download them, Apple.com states that we need to delete our entire music catalog or library, set the option to enable the lossless/dolby atmos to wifi/celular and set the quality of the songs to either lossless or high-resolution lossless and then redownload your entire music library if need be for it to be available!
I have 89gb full of songs but I have set through a smart playlist so it's easy to download all of them, with that said after redownloading all my songs my catalog went up now to 105gb from where it was before!
Learn about lossless audio in Apple Music and how to turn it on or off for your device.
support.apple.com
By the way because of my music size, i had to create a smart playlist, there’s a tutorial to have it recognize all songs that are longer than a second or 0.00, if you need help I can screenshot the settings and anytime you manually delete them by accident, you can add them all individually including music videos!!!