Diamond 1 is like top 40%, it's basically equivalent to high gold or low plat in most other games. By the time you get your MMR high enough to play vs good onyx players, you'll constantly be playing vs controller players who hit 65% or higher accuracy.

You literally cannot take them in a 1v1 - my entire gameplan is basically to not 1v1 controller players because they will literally beat you every single time. You have to treat controller players the same way you'd treat someone you think is aimbotting - outplay them using nades, positioning, movement, and teamwork.

For the record, I've played FPS on PC for 10 years, including at a competitive level and am LAN proven. If someone as good as me is outmatched in accuracy vs controllers, regular players don't stand a chance.