My biggest fear or doubt with him by fair is that I do not trust his press resistence when under pressure, and his ability under pressure. For this, Flick will always opt for Olmo or Pedri provided he has the squad depth.
Fermin will be for lower quality opposition or sub when the game has space to exploit.
Different profiles, but imagine what Fermin can be if he keeps working hard and progressing when he is 25/26 years of age.