If he chooses the Dolphins then it’s simply about location (and maybe money since they have the most cap and no state income tax). If he chooses the Chiefs, it’s about a chance at a ring. If he chooses the Bills, then he’d be entering day 1 as the lead dog with plenty of opportunity to play a feature role to improve his value on an up and coming team with a chance to contend.
Tough call, but it’s really about what he values most. If it were me, I’m going to play with Mahomes for a shot at a ring. Especially, since I made 28 million for my last 18 games. But...and I’m obviously biased, Buffalo is really a great option for him to play and contend.