I think we can buy him in January for 40m. It's gonna become a bidding war in the summer but other than City and potentially Liverpool, I do not see another threat and neither can offer him guaranteed playing time due to their system. There's also Bayern but I doubt they'll spend so much in January.
He'd never move to Man Utd, London clubs are not appealing, Milan run out of money, Juventus is another threat but without selling Higuain it is unlikely that they're making a striker move as they still need to move Mandzukic and a couple of others.
Barcelona won't go for him, PSG is stacked and Real Madrid will only move for him if they panic though I see them going for a higher profile player instead.
Just make a bid of 40m and let him stay there until the end of the season if that sweetens the deal for them and in such case sign Zlatan in the meanwhile for the last 5 months and we're set.
I don't think there's a better chance for us to lock him up than in January.
Lautaro + Haland is a scary duo with Alexis Sanchez possibly interchanging between the two. Esposito can also gain (or clash, you never know) from having a teammate at a similar age that's so fucking crazed up mentally. Zlatan would be the perfect mentor for him though.
Our midfield is the priority but we sacrificed 100m on Lukaku and Lazaro who do not improve us in either short term or long term, so maybe an investment of this sort is calling. There's no midfielder that we can sign in January that has this effect other than Eriksen and I doubt he'll leave for us then when he could join Real/Barcelona for free.
There's like 6-7 midfielders we could sign but they can wait until the summer. If we sell someone, which is doubtful, we can simply loan someone to patch things up and we should be expecting around 130m from sales from the loaned out guys to get a top midfielder + some quality rotation players of Sensi's level.