Need a very good CB and a creative midfielder minimum if they’re going to get top 4 next season, but they will be way to tight to sign two of Ake, Akanji, Maguire, Maddison, Brooks, Lo Celso.
Except them to finish 5th or 6th
Because they play a 10 and they're out of fashion, they should be able to find a quality player on loan or undervalued if they're clever. James Rodriguez or Fekir or even Odegaard make little sense for us, for example, but could have good seasons as the Arsenal 10.
Ziyech seems like the guy they should probably go for, even if it takes 2/3rds of their budget. Genuine upgrade. Works hard, can play either wing when they want to go 4-3-3 or 4-2-3-1, he'd have 2 guys looking to get on the end of passes in Aubameyang and Lacazette in most setups and when Ziyech gives the ball away as a 10 trying overambitious stuff as he's wont to do, he'd have an extra player in behind to deal with counters.
They do badly need upgrades at LB and a CB too though, and have apparently not enough money. Might need to go for a cheap option they believe in at one of those, feels like LWB would be easier to find one of those guys.
Ozil only has 2 years left on his deal, so not an insane risk for a team in Italy to take, shifting his wages would cover a decent (10-15M) punt on a foreign fullback or Champo option if there's one out there better than Kolasinac.