Hardly anyone is genuinely arguing that João Neves is going to transform us into a Top 4 side, to be fair; that's reductio ad absurdum, not a good faith argument. What some do think is that, given his qualities, he would give a boost to our midfield collective, and form a potent long-term partnership with Kobbie Mainoo (provided the coaching and organization is up to scratch (as that can throttle talented players... we need look no further than Enzo Fernández and Moisés Caicedo at Chelsea), and they strike up a decent understanding). Signing someone like him would also not not equate to ignoring other positions, if the club makes the right manoeuvres in the mercato (particularly identifying budget-friendly squad options and wrt. player sales, which would lead to a maxmization of resources).
Also, folk seem to have this idea that we must first build a squad on the cheap (including that rather unpleasant
@Hammondo chap), and then add quality pieces — as if that's the only way of going about things (and also as if accounting techniques like amortization are a figment of our imagination), full stop. One does get the sense that this line of thinking is informed by the development of, for example, Arsenal in recent years (who went for relatively cheap options first, and progressively loosened the purse string to splurge on the likes of Rice, Jesus and Havertz) But we should note that Manchester United always has some of the highest revenues in club football, even when the club misses out on the Champions League — and has lots of wiggle room to sign difference-makers, even with FFP and PSR concerns.
In comparison, Arsenal trailed the heavyweights by €200 million or thereabouts in terms of annual turnover, so they were forced to abide by smaller budgets as they went about refurbishing their squad. That isn't to say that we should waste money or pay over the odds for players who are not top talents (as we did for Antony, among others), but if the right profile of top talent is available, we might want to make a serious move instead of throwing our hands up in the air in defeatist fashion. Should also add that I dunno if João Neves is going to be worth a €100 million fee, and am not arguing that we should compulsarily cough up that much money for him.