People keep talking about taking the next step, that isn't going to happen by gambling wholesale as per the 4 players in the OP. Although we need 5-6 positions upgrading I'd be OK with 4 addressed this Summer so long as they are high quality actual improvements to the first team and not just gambles on potential.
United have gambled on potential with Lindelof, Chelsea have gambled on potential with Rudiger, both of whom are considered good but inconsistent at their relatively young ages, but they can afford to do so as they already have established players in those positions. You won't see United gambling on potential for their new striker, nor Chelsea for theirs. City have bought established stars for the first team or players already considered world class 'starlets' (Jesus - and that's already paid off). Arsenal have bought two established, and proven high quality, players.
Are we going to even maintain 4th if we don't match the quality of those transfers ? Damn right we aren't. We can debate, and have disparate views, on what VVD's real standing as a CB is, but the fact is whatever we think enough people in the game have called him 'world class' (or 'potentially WC') to give him credibility at least. There is no doubting Naby Keita either considering he's done this for two seasons now, inc. the major step up from the Austrian league to the BL, and he still took it by storm. Nobody doubted Kante for a minute when he went from Leicester to Chelsea.
There are no guarantees with even established world class players, they can still flop, United have had a handful recently, but the chances of us having a team (and a squad) capable of challenging for the PL and CL are invariably higher the more established and proven, the players bought.