Basically just start with what you’re aiming to enable and work backwards (as you’ve started to do). With judicious use of grep find out where that symbol is defined. If it’s in arch configs for other arches but not your own, it’s probably that.
There may be better tools out there to do this, but in my experience just sleuthing it out a bit will answer your question. The Kconfig system can be complex, but the files are pretty readable.
I default to piracy too, but I’m guessing you don’t listen to a lot of new music. The thing a music service offers isn’t just access, it’s discoverability. It didn’t replace my FLAC collection, it expanded it. What it replaced was listening to the radio to find new stuff.
For video I’m more with you. I’m happy to rely on word of mouth. Especially since the streaming services drop movies all the time and discriminate against watching in a browser. Getting a good rip means you can watch it anywhere, anytime, and not have to worry about it disappearing.