First of all they recently introduced a rock-paper-scissor system (HC>Know-How>Charm>HC) with 20% dmg amplyfier. He is HC you are KH so he deals 20% more dmg to you. Combat heavily relies on critluck and I frequently encounter wins/loss against opponents with 20k Ego differences just because one person got lucky crits and the other one got none.
In your case, he does not only get 20% extra damage, but also his defense (his KH value) is higher than your HC defense but attack difference is not too big. Pretty much nothing you can do as most people are HC (as it was the only specialization in the beginning of the game) - everyone who is knowhow has to deal with a above average amount of bad match ups. The defs just didnt not think that through as usual.
Let alone that it would make more sense if strength would beat charm and loses to know how and charm beat knowhow and not the other way around.