If you like to listen to music a lot on your mobile device please always look for these things in the phone you might want to invest in:
DAC(Digital to Audio Converter), most phones these days don’t have a jack so this might be hard to find but LG phones still have this option, otherwise make sure your device has Bluetooth 5.0 standard which helps a lot too with wireless audio accessories.
Stereo speakers can be great for a listening experience with no headphones attached, sometimes its just convenient to play music loud and having a good pair of stereo speakers can make that experience great.
Lastly if you game a lot then its great to have front firing speakers in addition to stereo speakers.
Some phones that have good speakers in no order: -Pixel 3 and XL -Razer phone 1 and 2 -iPhone XS, XR and XS Maxx -LG Thinq G7