Best price for android with trade in?

I have an iphone XS 256gb and next year I'm thinking of switching to an android phone. Where can I get the best value to put it towards a different device. I dint want to just get some money for my phone (music magpie) I want to know if for example a brand will give me more if I go direct to them yo trade in my phone for there's.

You will get more selling the phone outright.