This isnt true. His average position is literally all over the pitch
https://breakingthelines.com/data-analysis/an-analytical-look-at-bruno-fernandes-in-possession/
Its the whole point of the double pivot in an attacking sense. He has the freedom to go drift anywhere and is the reason why he is so difficult to pick up.
Its not even that hard to spot. Its why his pass percentage is so low. He is constantly trying to play the through balls to the forward line from deep positions and is the attacking link from Fred and Scott to the attackers.
If he played as high as you think he would constantly be isolated since our other midfielders arent very good in the final third hence our performances pre Bruno. Our midfield would also constantly be overrun against the 3 man midfields that literally everyone plays these days.
Playing Bruno high up would be tactical suicide. Nobody plays with a 2 for good reason.