You can't call yourself a 'duelist' player when you only play Jett as your duelist. A duelist player should be able to play all duelists, or most of them. If you only play Jett or Chamber you're just an 'operator' player.
Whenever you decide to duel its always 50/50 that's why pros do it only with support utilities to make it more than 50% of surviving
In ranked, especially playing on Jett/chamber is not fair dueling coz of escaping ability. Even bad players can top frag on Jett coz her dash makes 70/30 chance to kill & survive. You won't be punished for stupid decisions.
That's why such braindead pros like t0nz, heat, cned etc were washed up whole Chamber meta. They couldn't even adapt to another escaping agent (chamb) so why would they play well on agents without escape abilities? There is no way.