I have had the Equalizer Pro (EP) app loaded in my iOS devices since my early iPod Touch days back more the 10 years ago. The original reason I loaded it is it enabled FLAC, APE, and OGG playback on my iPod Touches. Later when iTunes became unusable to add personal music files to on My PC I have used EP file's function to load personal music files into all of my iOS devices since. iTunes in one of it debloating updates dumped the file feature when it moved the App store out of iTunes on the PC. I had to load file via EP WiFi loading function. I will not describe that here it works OK but a little hard to setup. Today I was working on the files I am transferring from old drives and I opened the iPhone tab in Finder. What I saw was the screen I used to have in iTunes on the PC. You could not manipulate the Apps but showed all of them under "Files". I opened EP and there was the screen I used to drag and drop music files into. I just finished dropping 58 GB of personal music files into it. Most all of this stuff is not found on Apple Music, or anyplace else Stateside. The complete Harry Potter books UK editions narrated by Stephen Fry, there are differences from the Stateside editions. Plus some of my Old Time radio shows. These are all loaded on your iPhone so if you are on a long brain killing flight to dark ends of the earth even on Airplane mode you have hours up on hours of music, radio shows and such to keep you sane.
The Equalizer Pro besides storing personal music and audio book files has a killer graphic equalizer
The Equalizer Pro besides storing personal music and audio book files has a killer graphic equalizer