Nah I disagree, there's more to the game than aiming, teamplay is very important. When you see high Radiant streamers and pros play Clove/Reyna in ranked you'll notice they play much differently than your teammates. Even on "selfish'' characters their teamplay is leagues above even immos I'd say
Reyna is the worst offender imo, for example you can play in a really bad position, still get one because you out aim your opponent (or your opponent is just oblivious), even if they're in a good position and get out for free. When you inevitably rank up doing that over and over again you'll end up facing enemies who'll actually will be able to punish you, and you'll hit a wall. I've had this experience and many of my friends have too. I've seen some youtube coaches cover it too.
as I said before if you want to play the agents for fun that's completely understandable, but if you really want to focus on improving it's a detriment
btw just so I have the full picture, are you a Clove/Reyna/Iso/Chamber main?