HELP. Music plays through my phones top speaker and car speakers when connected to aux

[Grey Shadow]

So I have a moto one 5g uw ace, it nevers plays audio through the top speaker, only for calls. but when I connect my phone to my car using the aux cord, my youtube music plays through the phones top speaker and all my speakers in my car(Chevy cobalt), and I definitely don't want my phone speaker to be used.(and quite possibly blown due to how loud it plays through my phone speaker) Help please.

Ps. It only plays through my phones top speaker, not even my main bottom speaker. Very weird.