Well I don’t remember if you watched him in Spain but his career didn’t exactly start at Arsenal, he played 150+ games at Atlético and was excellent in terms of physical reliability, just look at this shit:
When we played him two seconds after he got off the flight from Ghana that should tell you something about how we do squad management here and why he isn’t playing towards the end of the season, we can’t control midfield and lose every other game.
We don’t even have 25 players in the squad, another self-imposed issue, we had access to more players, we just fucked them up, gave them away or loaned them out, and then we just played our best players every game like a child playing football manager except that we can’t load an old save file.
Squad depth and management starts showing in the last portion of the season.
The squad is full of young players who lack consistency and bottle it under pressure which is normal, and that’s again self-imposed, poor squad balancing and whilst next year they will likely all be better, so will probably all our competitors with more balanced squads so no trophy for that.
On top of that we will probably have lost some or most of our experienced players like Auba/Laca/Elneny/Leno. I mean look at our squad sorted by age:

We have 8 players older than 24yo, Pepe is bricked and should leave, Partey we ran into the ground, Xhaka, Cederic and Laca you all think are too poor and the latter should leave anyway, Leno isn’t playing and might leave, Holding and Elneny are backups and never will be good enough.
I know we salivate about the prospect of buying one or two top tier quality players to add to the squad- man we need quantity as well, this was one competition, players are leaving and next season we’re starting out in four competitions.
We would probably be better off just buying 5 Spanish 27yo Dani Parejo regens for £30m, one in each outfield position tbh. It’d probably be the best patching up we could do here, this squad building is an absolute rookie shit show and I do put it down to an exceptionally weak season by Chelsea, United and Spurs and lack of a traditional outside one-season-wonder rival as to why we’re even still within reach of top 4.
We have a lot of work to do here, and it will be tougher to fix in one window in the likely event that we miss out on CL.