Can't transfer new music to iPhone library

I recently purchased three albums from the iTunes store. Two of them are in my iPhone 12's Music app library, and one is not. When I browse for "more by this artist" I can find the missing album and it shows that the album was purchased. When I click on the three dots and select "move to library" I get a pop-up telling me to "Subscribe to Apple Music". I have never had to pay for this free app before, why are we being forced to pay for it now? And if we have to pay for it, why did two albums show up in my library but not the other? I have seen other questions regarding this Apple music subscription thing and the only solution others seem to suggest is to restart your phone, which I have tried.