Cutthroat Kano gets f2-series or universal f4 xx special on pretty much every d2 in the game except Takeda.
People who play NRS fighters exclusively are generally terrible at punishing and always blame the lag or something else, when it's really a fundamental aspect of their skillset as a fighting game player they seriously need to work on. You need to get used to the varying amounts of blockstun and practice punishing. Letting go of block as soon as I block something unsafe and mashing a first hit of a string at a medium pace, then committing to the rest of the hits when I see my move come out works for me (in cases of heavy blockstun). As for special attack reversals you should do the input multiple times immediately after you release block until your attack actually comes out, that way it'll come out frame perfect every god damn time.
Overall there is not a clear cut, single way of punishing everything, things are blockstun, character, range and frame specific. You just have to find a way that works for you and your character. Some characters are just better at punishing then others and that's it.
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