On a different level, but from the comments I'm reading on social media, he reminds me of Ayuso. Ayuso was much more professional than the others from a very young age; back then, altitude training wasn't so common for juniors, and Ayuso was doing it with a private coach since he was 15. He also had a private nutritionist because at that moment at Cadet and Junior they weren't so strict at that age.
He reached the podium in the Vuelta a year younger than Pogacar, although his performance wasn't as impressive, although he was more regular, something distinctive of someone more professional than someone young.
That was enough for some to predict he'd have a year's advantage over Pogacar in everything. Still waiting his first victory in a GT.
Ayuso is still very good, but if we look at his development curve, he's probably barely improved; he's maintained his base level which was very high.
On the opposite end of the spectrum, we have Vingegaard, who at 22 was still in the U23 category, being beaten by many cyclists in the Tour de l'Avenir and other races. He turned professional at that age, and he was domestique, and his growth curve has skyrocketed compared to Ayuso's, who doesn't seem likely to have a significant improvement.
Morgado is another example of someone who, from a very young age, has and adult-level performance. He's probably in his professional prime at just 22.
We'll see what Seixas' future holds, but we're talking about someone who was already training at Decathlon at 16, while cyclists of previous generations at that age were in amateur teams or clubs without any altitude training, etc. Pogacar didn't even have a time trial bike at 17; now that's unthinkable with the WT development teams.
I think we're going to see a generation with a growth curve similar to Ayuso's. A very high level at the beginning, but without bell curve.