Think he wont be "eating away minutes" from anyone. Xaviball is as intense as Pepball in terms of total pressing of the opponent for 90+ minutes. It demands a lot of stamina and will accumulate fatigue. It's probably strategic signing to have swarm of players, especially mids, who can be interchangeable for this system. Obviously, like the most skillful will play the key matches, while likes of Kessie will be rotated in and out in easier matches and subbed in, when score is favorable. Don't forget that Gavi and Nico are far from finished products and will have to deal with being switched in and out until they mature. I like management that makes pragmatic signings with clear strategic point and this is it.
This also why Xavi wanted Torres. Not just as an attacker, but one, who will be very good in his high intensity setting. Still a bit baffled by Morata urges, but i can bet that at least 50% of that was because of his work rate off the ball both in attack and defense, which is why Lucho likes him too even tough he sucks as a scorer.