I use my oneplus 6t with a dongle as my DAP since my fiio x1 finally broke.
I would absolutely not use a phone as a music player cause

1. you use up battery you need for phone to function as a phone
2. unless your music horizons are non existant or you only stream, your phones memory is used up with half your library
3. the solders on ports will work harden and will break leaving you with a very expensive brick

Just get a dap for 300 that will last you a decade.