On my PC, everything is intact. That is segregated from anything Apple or iTunes related. My biggest issue is having this on my iPhone and the only access to it will be if I maintain a subscription for a service I do not want or need. By my read at Apple Support I will lose access to even the stuff I physically put on the iPhone when the Apple Music service stops. WTH should I have to pay Apple $10 a month to listen to music I already own? without ever downloading anything new from Apple?
Looking at your response, you seem to have access to your music on your iPhone without maintaining the subscription to Apple Music service. I will be attempting your suggestions on my sons phone shortly, next time I have 3 weeks to commit to simple file transfer.