I'm not sure if this is a good comparison or not, but I think he'll follow a similar pattern to Pedro Neto at Wolves - who's been their best player this season.
Neto struggled to get in their team last year - against the likes of Jota, Traore, etc - and only showed flashes, without ever putting a consistent run of form together.
After a year of learning and being given more minutes he's now grown into his role. This is exactly how I see Ferran being next season.
It's a well trodden path and we've got loads of examples of our own, including Silva, Toure, Sane, Cancelo, Rodri, etc, so it's an obvious prediction to make.
He's got too much going for him to not reach really the top with us/Pep.