I'll give you Mahomes because he's proven he can play at the highest level even when outside of TE he doesn't always have elite talent all around him.
Burrow? He's been great no doubt, but look what he's got around him.
Give Josh 3 Pro Bowl caliber WRs, a very good RB and TE and a above average OL and see what happens.
Look at what Hurts did when surrounded by elite talent. Parlayed that into the biggest contract of any QB currently. He's good but are you taking him over Josh?
The Bills will be doing Josh a huge disservice if they don't match the offensive talent of the other top teams because it's only getting harder from this point out. 2 years ago we only worried about the Chiefs. Now the Bengals have surpassed us and the Chargers, Miami and even the Jets are coming on fast.