On the contrary, Tanya actually, literally has a male brain. She must, or its fundamentally not Tanya. The brain isn't the seat of consciousness. It is consciousness. Your consciousness does not continue existing if a shotgun blows apart the structure of consciousness that is your brain.
If Tanya does not have the exact same mind as Salaryman, then it's not Salaryman in another body. It's a body with a mind that is based on salaryman, and Salaryman died the day he meet Being X.
As Being X is doing this to Salaryman to prove a point, Being X does not serve his own interests by making up a new person that isn't the one he wants to teach a lesson to. He has the power to change Salaryman/Tanya's mind to be his bitch if he so desires. He chooses not to, because he wants to have the respect of Tanya given to him of her own free will. Tanya has the same mind as Salaryman when she is formed in the new universe. Exactly the same, not even a synapse changed.
Salaryman was a sociopath, psychopath and any other kind of nutcase you can think of. His brain had abnormalities that meant it did not respond to emotional hormones. Ergo, it will not respond to any differences in brain blood chemistry that would be present in his new body, either.