He’s one of the most overrated supports in the game. He lacks flexibility because he is only good in one comp - ones that take advantage of his ranged heals.
He’s great in dive comps because he can heal a diver from a mile away while also slowly chipping away at opposing squishies, which allows divers to hit their combos easier and win 1v1s
But thats it. Jeff is not flexible or versatile. He is a liability in any other comp. His CC is weak. His burst heals are poor. He has a ridiculous headshot hitbox which makes him food for poke. He needs the assistance of peel much more urgently than other supports while not really having the output to justify needing so much defense. He has the only ult in the game that stuns itself when failed - and that is compounded by the fact that when he ults - even if he successfully does it, his team loses a healer as he can’t heal while ulting obviously.
Jeff is supposed to be a niche pick intended for the proper comps. Please stop instalocking him every game. In most matches a Jeff does more harm than good.