Not so sure about this. See what contract they gave to Ansu. So pretty sure they'll do the same with Yamal and Cubarsi.
I think they learnt their lesson with fati, if memory serves me right, Araujo wanted a contrast similar to fati's and they said no, gavi didn't get that kind of deal either.
Fati situation was unique because we had just lost Messi and the club thought they had in heir in hand, so they went a bit crazy giving him the #10 and a big contract.
Think they've since learnt injuries or multiple other factors can affect a young players development.
I think he and yamal, will probably end up with a gavi contract, who if we look beyond the hype was better/more impactful than both for the first team when he came through.