Struggling with the IOS Music app

[Kenji]

I've been using iPod Classics forever it seems to carry and play music on the go and in the car. My last iPod Classic 160 gb is still going strong, but now I also have an iPhone 11 and a car with Apple Car Play, multiple bluetooth headphones, so the iPhone is my go-to music player now. But for some reason, I struggle to play music in the car on the IOS Music app. I have a huge library in iTunes and don't use the Apple Music or Match services. The IOS Music app controls elude me. I struggle to get it to play an album or a playlist. When I do play a playlist, the play order is not as I set it up.

Is it me, or is the app a mess for playing albums and playlists downloaded from iTunes? Is there a better player app for ease of use in the car with Car Play?  Are these stupid questions?