All I can say is that I use iTunes every single day. It easily handles a massive media library of film, TV and music that is a mix of ripped, iTunes (and other) purchases and Apple Music added tracks. It streams to two Apple TVs and two Airplay Speakers. It’s trivial to search for music and add it to Up Next and then it smoothly reverts to my previous music playlist. It’s controllable via my iPhone or Watch. It’s easy to add videos to my iPad when I’m going travelling or to create a local backup of my iPhone when I need. iTunes UX and UI are fine. It works fine.