RNG is only starting to become somewhat relevant in the 95+ range with 99-100 definitely relying on it.
You can hit orange with really bad RNG if you generally play very well; you don't even need to pull really crazy AI stunts with tons of lucky MP ticks. RNG is really the last thing you should ever look at, cleaning up everything else is far more important. Sure, you have some variance when playing the crit set and it can amount to several 100 dps but mistakes make for a greater dps loss.
Good dps doesn't depend on RNG, but high ranked pink parsing does.