Hi guys. I use pio solver and GTO approach helped to improve my game a lot.

but I think I have some leaks on preflop playing.
my 3betting freq is around 9%. I think my 3betting strategy is not terrible. but I have 2 problems.

1) what kind of hand should I make 4bet against villian's 3bet. (including cold 4bet)
2) what is my 4betting range?

and these days I saw some 200nlz+ regulars just 4bet-shove on hot zone. I can't understand it but I want to know the strategy.

I want to make solid strategy on every position. but it's hard to solve.
should I watch more rio coaches video, or should I buy preflop solution like monker solver solution?