I've put off updating my MacOS (High Sierra 10.13.6) for yrs because I'm worried about what'll happen when doing so forces me from iTunes to Apple Music. Now apps like Slack & Chrome are ending High Sierra support. Will updating nuke my local music files? Is that preventable? I'm open to other apps. I've heard good things about Swinsian for years, but it doesn't support syncing local files to iPhone, which is a must for me. Anyone have solutions, either within Apple's ecosystem or outside of it?