Honestly not sure how much i agree with this. The real primary reason the scharn performs so well isnt its tankyness imo, its the gun characteristics. The thing is incredible at dealing with cruisers and smaller ships. Between its fast firing guns and extremely good turret traverse, it rips through most things that arent BB’s. It does struggle significantly more with BB’s though, to the point where sometimes the only actual reasonable recourse is to close the distance and torp them. THATS where the armor comes in. It can be hard to sink fast enough if its rushing you, at that point though, you focus more on the 2 forward turrets and the conning tower to limit its firepower and maneuvers, and then use HE to knock out the torps, and you’ll chew through its crew.
I think if it went up in BR and faced more fast battleships, its effectiveness would tank to the bottom and lead to it getting downtiered back to 7.0