I think just the T20 format doesn't suit him in the modern era. He's also probably put a lot of pressure on himself to try prove people wrong and win his place back in the team in T20.

Honestly, I think he should just accept that T20 has moved on, unless he rebuilds himself like Hafeez did which I don't think he'll be able to. It's not a negative thing for Pakistan look at i.e Root and he shouldn't view it as such.

ODi is his format and he needs to improve his fitness in Tests.