I think part of the angst around Sesko is a sense that the window of opportunity is shrinking. Rodri is back next season, Liverpool are getting Wirtz, and Saliba only has two years left. If we don't win next season, it'll only get harder to do so.
Put it this way - if we’d won the league this season, maybe Wirtz would be coming to us. Maybe we’d have made a more compelling case for Isak.
Basically, we can't keep missing out. Because if we do, it won't be long before Chelsea, Newcastle, United, etc. catch up. Going from where they are to where we are isn’t as hard as going from where we are to 1st. And the longer we stay where we are, (a) the more likely we are to get caught, and (b) the harder it becomes to overtake the teams ahead of us.
We need to get this summer right. Maybe Sesko ends up being the answer - but the stakes are high and it cannot go wrong. If he has a slow start, we'll see what we saw with Havertz when he joined and it won't be pretty. Not saying that it would be the appropriate response but it is what we will see. That energy won't be good for the player or the club as whole. This summer is the most important window of the Arteta era and I hope the clubs gets it right.