Nope. Benzema is extremely flexible in the way he plays and used to adjust his game to someone else (Ronaldo). I can easily imagine a 3421 formation with Haaland as the target man and Benzema and Mbappe operating in the half spaces around him. Would be a true Galactico attack.
On the other hand it is interesting that in the last weeks more and more often the option was reported that Haaland could actually stay at Dortmund for another year. He clearly likes the team, so it might really be a case of "I've got time, I have fun here, I don't want to leave now" (and Dortmund reportedly being interesting in signing a contract addition to get rid of the clause for the summer would also mean he gets good money for it). Might even be the case that this is because they already are aligned with Real Madrid that Real will rely for another season on Benzema, and that Real have a Galactico signing ready for 2023, following Mbappe in 2022.
Haaland is not a target man but rather playing off the shoulder to use his pace & getting into the box.
Benzema was absolutely horrible between 2016-2018 when Cristiano played as a striker, I don't buy the myth of his "extreme versaility". There's a reason Benzema's numbers drastically improved as soon as he went back playing as the lone striker. And I honestly doubt Benzema would become a 2nd to anyone given to what he has done in the past 4 seasons.
Ancelotti will never use a 3421 formation to feck up their balance. Vinicius is undroppable and both him + Mbappe needs to play much closer towards the goal.
It's clear Haaland's time at Dortmund is over, the club prepares to sign his replacement in Karim Adeyemi and Haaland himself wants to play in a bigger club. Joining Man City is easily far & away the best option in summer 2022 and it's not even close. They've 0 strikers and Haaland would improve an already ridiculously good team to the next level. Haaland could become the best striker in England since Jimmy Greaves with the insane service from teammates like KDB, Foden, Bernardo Silva, Gundogan etc.