To work out, when searching for a song in Apple Music, while writing the name of the song / album, you should become a predictive opportunity before you hit search, right?
This has changed since I changed the AppleID region, now I can only see results when I hit the search, the only suggestions that appear are artists. No song suggestions or album titles until I turn on searches.
I have the iPhone XS Max, iOS 12.3 and the problem existed long before (some months at least). I changed the region from the US to Jordan (if that helps).