Possible Solution:
Here is what I posted on the Apple Support Forums earlier today (iPhone iOS 14.7):
Wow. What a coincidence! Been having the same issue (always with Shazam downloads) and got off of the phone yesterday with two Apple techs and went to the park today and my problem appears to be solved! I also noticed that my problem seemed to occur in my car a lot but then noticed that when I 'disconnected' my iPhone from my cars stereo ...the problem went away. At the park my settings were:
Dolby Atmos: Automatic
Audio Quality: Lossless Audio 'ON'
Wi-Fi Streaming: Lossless....>ALAC up to 24bit/48 kHz
Downloads: Lossless .......> ALAC up to 24 bit/48 kHz
Also....under Music....'Allow Music to Access'......> Cellular Data 'OFF' ('ON' , when it worked once/twice before , was on of my gripes...who wants to have to use data to play music).
And: AirPods Pro.....> 'Spatial' set to 'On'
Hopes this helps. Also found out from the techs that some songs, downloaded from Shazam or otherwise, might not play because Apple Music has lost/never had rights or the artist pulled the song.....so , just because Shazam says it has downloaded a song doesn't mean it'll play!!? ! When this happens you may get a dialog box stating : 'Cannot Open...This content is not authorized' . If you get a 'Connect to Wi-Fi or Cellular to Play Music' dialog it means you haven't used Apple Music for that Song or Playlist in a while and simple have to re-download. Preferably using your home Wi-Fi. This was a gripe of mine with AM years ago but one of the technicians told me it's been 'fixed' provide you have 'Synch Library ' on in Music settings. Time will tell on this but I've gone back to putting a monthly reminder on my calendar to 'Dnld. Apple Music'.
Hope this helps as many as possible.