If MC already deviated from the original game plot do much as to getting different people expelled then there's really no need for an isekai setting where the isekaier uses his game knowledge to his advantage to overcome pitfalls right?
Now it's just hardworking guy and his two wives.
The monster or maybe the final boss might be stayed the same.. The information from the game might still be useful
He's hardworking that's why he got those two girls fall in love with him.. He forgot in the original story those two heroines fall in love with the original MC because the original MC is hardworking..
But because he is forgot and got more training than the MC.. Those two falls in love with him..
He is to focused to stay alive.. He does not realize how easy the heroine falls in love with him..
Don't forget he also make the original MC to defeat and expelled the top student 🤦..
He make a big mess.. He does not realize he create even trouble than the story intended to..