I've been coming across a few very good and winning (quite a lot) 6max regs as of late who do the following:

-3bet 9-11% from every position vs every position

-3bet to a super small, almost have-to-call size

-low fold to 4bet (low 40% range)

-play well postflop and fairly (bot not overly) barrely on the flop and turn

I believe they are doing this with a fairly unpolarized range from what I have seen. Since they make very few mistakes postflop, I am having trouble finding a good way to combat their aggression preflop besides 4betting more and widening my 4bet value range a bit. Any suggestions?