Why does a game with a combat based on dice rolls still have a PERCENTAGE of hitting chance? And who balanced it? Why 6 attack rolls at 65-80% are SIX LOSSES?
You do realize those percentages come from the actual dice rolls, right? Not all of the rules/mechanics are implemented correctly according to 5e, but those percentages of hitting chance represent the probabilities/statistics of those underlying dice rolls. This part of Larian's 5e rules/mechanics implementation I actually like - better than using
https://anydice.com/ or trying to estimate those probabilities...

You can see the actual dice rolls in the combat log.
When you play TTRPG (which is the proclaimed intention of Larian), you do not say "you have 35% percent chances to hit"
IF you say a figure (because you do not have to say it), you say : "You have to roll a 14" (on a d20), (and if you want to do the math, then you precise if you roll is with advantage, disadvantage, or normal)