What someone with close to 70% win ratio and 60+ games is doing in bronze?

I just want to understand the math behind it. Because I cant come to any sensible idea as to what possibly drives Blizzard matchmaking and ranking system right now.

Im a very average player, maybe even below average. Mostly in gold during OW1. In OW2 I got ranked into bronze, together with all my playing friends. From time to time when I see someone in the enemy team who performs good (certainly better from what I remember from gold in OW1) I inspect that person’s profile. 95% of times it is private (this default setting is garbage, I want to know who I play against dammit) but sometimes it is not. Yesterday I noticed a good playing Sojourn and checked her profile. She was in fact bronze, but her win ratio in current season was around 70% and she had 60-something matches played. My question is, what sane and not totally broken system thinks that this person still belongs in bronze? And how am I suppose to climb if I have to play vs. people who are at least 3 leagues above me in skill? Does ranking up even work right now? Does anyone know how? My win ratio in entire OW1 was around 50% as one should expect. In OW2 it is below 40% right now (30-something !) despite often me being a top performer in my team. I never had such low win ratio in any competitive game I can remember. Not even in any which I barely started to play (as then I played vs other noobs). Does OW2 MMR even work right now? Or everything was reset and right now it is all just a big bag of randomness and I should stop playing for 6 months until this gets sorted (if ever?).