We were talking about a turn c-bet range ( 31% bluffs vs 16% bluffs) not a flop range (tho 48% there is also too much IMO), and on this board 31% is too much, I have shown that even QJ has a profitable call, which means SB is overbluffing, because these hands should be dumped if SB bluffs with a correct frequency

Even K8 (which should be folded otherwise) has a call on most rivers

You can ofc donk x your bluffs on the river to bluff 13% instead of 30% but then when you x CO knows that you have nothing but a bluff,and that is the most readable move that you can make.
And CO doesnt even have to do anything special with K8 its enough that he folds or x-s it as usual, its EV increases anyway, because on the turn it gains twice as much % from the pot than it should ( 30% vs 15% ), and this is also true for every hand in his range, the EV of for ex. KK increases the same way.
And I dont use an incorrect model, because I dont use any model. IMHO there is no such thing a 'correct model' for bluffing, that tells you need to bluff X percent on every turn for example, because there is no uniform number for bluffing% on a street,because every board is individual and different from the others. Instead of looking on X as a constant I consider it as a variable.