It is already explained before. Back in march he was called uo for U21 Spain in Euro U21. He came and trained with them then he only played 8 minutes. After that he was dropped. Back in 2020 he played three matches with them and he was terrible (you can watch his performances on youtube).International coaches? Are we going to default our judgement to the opinions of people who don't watch him play anymore than we do? That's ridiculous. A coach's opinion has wheight because they see him in training everyday. International coachs base their picks much more on what they've seen on the pitch and naturally we haven't seen anything from Puig because he hasn't played.
Pre 2020, no one laid an eye on him. If he is that big talent, they would notice him anyway. I'm sure youngsters from Masia would have much higher chance to be noticed and scouted, compare to others from smaller clubs.
Pedri for example, at 16 he already played U19 World youth with Spain.