Well, now we're getting somewhere. Sort of. On my 2017 MacBook Pro, I copied the m4v files to the "Automatically Add to Music" folder and when I launched Music, there they were. But then, when I plugged my phone in, I wasn't able to copy them. So, I went back to my M1 MacBook Pro, and when I copied the same files to the "Automatically Add to Music" folder and launched Music, nothing happened.
I miss the days when Apple was the image of "user friendly" interface design. The company has now turned into another Microsoft, forcing everyone into its world view. I used to be able to "Add to Library" in iTunes and then copy to my phone with just a couple of clicks. Apple has done away with iPods, and pretty soon it will be impossible to play non-Apple branded/purchased music on any Apple device (those cheap mp3 players at Best Buy are beginning to look very attractive!).