scenario: a villain opens 2x on btn. i 3bet to 6bb in the BB.

i first thought this strategy is crap cause when u 3bet that small u should ('in theory) 3bet a wider range. and playing with a weaker range in a blown up pot OOP seems not great.

example:

i open btn 2bb, both blinds normal Regs unknown(30 hands). BB 3bets to 6bb. which ranges should i defend, which hands 4bet?

i also seem to get destroyed postflop against unknowns. they start potting alltime (like bet pot on every flop + turn). or play some weird lines with x/r or overbets.

and how should i react against a player who 3bets a 23% range? which ranges should i defend? they seem to destroy me post with this strategy cause they know i defend very wide vs the 3bet?

usually the players who use this strategy arent even good regulars or are even fishregs and own me with it. i dont have any problems playing normal 3bets pots etc.

thx