Either way I'd recommend getting a used 3DS. They aren't that expensive on the second-hand market and offer a better gaming experience than on a phone.
Playing 3DS games on a phone is cool for novelty and stuff but touchscreens controls don't even come close. Trust me, I used to do the same thing with DS emulation on my phone. Only games I could play were Ace Attorney.
I'll be playing turn based stuff mostly so touch controls shouldn't be an issue really. I'm just not sure if I'll spend enough time emulating stuff to jusitfy sacrificing AMOLED