I have heard that you should have a positive winrate for each pocket pair but what about other combos? For example I loose small with QJo/KJo, it is a very small sample(cca. 120 hands of each) but it made me wonder do players have a positive winrate on every combination at the stronger part of their range for example lets put a range of 21.9%(290 combos): 22+, A9o+,KTo+,QTo+,JTo+,T9s+
It's a pretty strong range, so do usualy winners over very big samples(200k+) see a positive winrate on each of those combos(maybe even more?).
If not are there any known combos from value hands(QJo comes to mind but it's subjective) that are known to be hard to play and often end up breakeven even for the winning players?