There's a chance he could find a new level, but at his current one Lautaro wouldn't be worth the money or even close to it. Can't even outscore Lukaku in a league where the likes of 40 year old Quagliarella and Immobile look like gods.
Might be simplifying it but I'm very tired of these 120m+ attacking transfers that come with doubts/question marks in the first place and end up not performing to our standards. I'd rather buy a much cheaper talent, someone like Donyell Malen from PSV. He's an exciting talent and looks to have the right qualities we seek in a forward, but at a fraction of Lautaro's cost. Aside from him we would still have Suarez/Griezmann to rotate in attack and Ansu who is a legit contributor in our squad and Braithwaite who has looked very good.
100-120m+ type transfers should be reserved for the RIGHT player at the RIGHT time, and more importantly in the right position too. Dumping 120m for any player based on panic logic doesn't make them worth it. It has to line up well and be a unique opportunity that fits well into our plans, with a player who is so likely to succeed that the risk is low. That is one way that top teams do it, break the bank ONLY if the case aligns perfectly. Liverpool did this well with VVD.
Better than us trying to be like RM who stack more talent than they need, yet still get good money and good reception for the fringe players on their chopping block. When we've tried to do that we've had more failures than successes and almost never walk away breaking even on our initial investment.
Right now what we need is a CB or even two, a starting caliber midfielder like Thiago to replace Rakitic, maybe a RB. Our attack absolutely needs reinforcement too but there are no standout options on the market right now that make sense on a footballing and financial level, and the board have been absolutely shocking in their attempts to bolster the front line with no plan or position in mind.