iTunes (Music) update 12.10.8.5 seems to have caused issues for my phone

All of the songs that I have added to my iTunes since 12.10.8.5 was installed (from non-iTunes sources) cut off the last 6-10 seconds of each song, jump to the next song on the playlist, tell me this next song is playing, but doesn't actually play the song until after what seems to be the same amount of time as the previously played song passes in silence. Any songs I had added to my iTunes library prior to 12.10.8.5's update (regardless of media source) do not have this problem.

The only other queries I've seen even remotely close to this concern are from at least 5 years ago and I cannot find anyone else having this issue. I have not wanted to use Apple's Music streaming options or Genius et cetera up to this point, but it sort of feels like they're underhandedly trying to force me to give up on having full control over my music by not allowing me to bring music in from other sources. (Previously saved on my hard drive from former computers, 3rd party downloads et cetera--though I still need to see if this also occurs if I pull from both an Offical CD vs pulling music from an old homemade CD...)

Also, this playback issue only happens on my iPhone Xr, and does not occur at all while being played on my computer.

Any thoughts? I'm trying to avoid reverting to a previous iTunes player and not trying to switch to another music app.

Thanks in advance as needed!