Or even set whatever stats you like for your character. I mean it is single player and if you have a 20-20-20-20-20-20 mr/ms Max(ine) Perfect.. well.. cheating but who cares.
Anyways there has been like half a dozen major ways to distribute stats from elaborate buys to roll 3d6 twice to 4d6 drop lowest and many many more. Even set 18, 16, 14, 12, 10, 8 in whatever stats you like or other such scores.
rolling 4d6 dropping 1 does not allow for 20 as a starting stat, 18 at most

Do people really reroll these until they are perfect in all stats?
Maybe my maths is wrong, in that case please correct me, but it seems to me that the probability to roll a 18 in one of these rolls is 4*(1*1*1*6)/6^4=1.85%
If you aim for k stats with 18, the number of tries you need for that is:
1/((6!/(6-k)!)*(4*6/6^4)^k*(1-4*6/6^4)^(6-k))
k=1: 10 tries
k=2: 105 tries
k=3: 1.388 tries
k=4: 24.519 tries
k=5: 649.762 tries
k=6: 34.437.377 tries
If each click takes one second, to roll a perfect character would take over a year
But I agree with you

We should be able to set stats. I do expect this to come as a mod if Larian does not add it regardless, so no worries...
Imo compared to most other systems, the stats do not matter all that much. On your fighter, you pretty much need str and con, and wis for saves. The other three you can dump. There is only a tiny amount of spells targeting int and cha (though cha has some famous ones like banishment), so they can be ignored.
So if we assume rolling three perfect stats and the rest do not matter, it takes on average 20 minutes. And of course, here, the race bonus is not factored in. If you have a +1 to a stat, a 17 would be enough to, that drastically cuts down time