Seixas is overhyped. The futures of young riders are generally very hard to predict because the uncertainties are so high. I was very confident back in the day that Quintana would become a Tour winner. In 2019–2020, I was also quite confident that Evenepoel would win at least one Tour (though I was never in the “Remco will become a dominant GC rider” camp).
I asked from AI (ChatGTP 5.2pro) some predictions and it gave Seixas 2-5% chance to win a TDF during next 5-8 years.
Specifially about Seixas Ai said: " chances based on historical outcomes of top U23 and junior super-talents.
The rough long-term conversion rates are:
Tour winner level: ~10–20%
Tour podium level: ~25–40%
Very good, but not a Tour winner: ~40–50%
Since Seixas is considered to be in the higher tier of prospects, then
so I’d place him toward the upper half:
➡️ Chance he becomes a genuine Tour-winning-level rider: ~15–20%
The uncertainties around Paul Seixas are massive. If he moves quickly—during the next couple of seasons—from prospect level to true contender level (meaning podium finishes in TDF), his odds of becoming a Tour-winning-level rider would increase dramatically."
I would say that AI is broadly correct in its estimates.