The rng, especially when attacking with advantage, definitely seems screwy to me. I can't count how many times I've missed with 88-95% to hit, when attacking from advantage. And not just once, but repeatedly in almost every combat. Also, whenever the dice say I have a 50% or less to hit, I just assume I'm going to miss. Because that's what happens just about every single time.
I've also noticed FAR too many occasions where when attacking from advantage, if I check the die roll for the miss, it will be 3. Not 1-2, not 4-10. 3. 99% of the time, it's a 3. To me, that seems like something's broken. Not only does it mean that rolling 2d20 my highest number was a 3, but it's CONSISTENTLY 3.
Beware, all the Wizards with their unresistable surface cantrips will tell you it's just confirmation bias and everything's just fiiiine, you just don't get how dice work!
