He is 18 and is already better than McTominay. I think that's clear. He's had an underwhelming season for him but has been a stats leader at 17 in a top 5 league. That alone is incredible and a strong indicator for his future.
Greenwood is considered an amazing prospect but for a forward, his advanced metrics are very average (30th percentile for xG, 32nd for xA). Camavinga's are already genuinely great in the relevant metrics for his position. Diallo is clearly a great prospect but Camavinga is slightly younger than Diallo and already has two seasons under his belt in a top five league. Generational talent is over-used but I think this guy is the clearest candidate to be the Mbappe/Haaland of midfielders and if we can get him at a good price, we should do it at all costs, especially when his stock is relatively low.