Just wanted to leave my two cents here.
First of all, I am portuguese and a Sporting CP fan, so I'm sorry if I show a bit of a bias.
João Félix is a great player, no doubt about it. But do we really want him at City?
Can anyone tell me what is his position? No, not one person can.
Is he a striker? No. He's not physical at all and doesn't create that many chances. He's not clinical (watch the play that got him a penalty against Leipzig, he could and should have shot way before getting fouled).
Is he a winger? No. He's not fast enough with or without the ball and couldn't cross to save his life.
Is he an attacking midfielder? No. Like I said, he's not intelligent enough to be a number 10, nor does he have the passing abilities to do so.
What he COULD play as is something similar to Messi's role on Barcelona under Guardiola. But honestly, for that, we already have Bernardo who's leagues above. If we really want to spend this kind of money we should either buy Havertz to play as a false 8/ false 9 mashup or just get Mbappé/Haland to play as a striker.
João Félix (and most players sold by Benfica and Jorge Mendes) is quite overrated and definitely overpriced. Same goes for Ruben Dias. They look amazing playing here in Portugal since at the moment the only other half-decent team is Porto, nothing else. But take a look at their performances in the Champions League and then tell me you want to spend 120M on Félix or 80M on Dias.