Its a unique line to say the least. I think i see your line of thinking. KK, and QQ can fold by river. Better Jx(QJ,KJ). I am unsure though if villain is folding and weak Ax here. Maybe but then its hard to know how wide is villain 3betting from the BB.
Even if your bluffing with the best hand, there's an additional element of not having to show your hand lol.
I think though that the solver is correct in not bluffing Jx combos that we should stick to some bottom pair combos. Allowing villain to have more Jx in their range seems really good for us here.