There are some players like Neymar, Bale, Hazard who had some excellent seasons and raised questions like will they win Ballon d'Or and take over positions of Messi and Ronaldo. So far we can say they will never be able to do that as Hazard and Bale retired while Neymar is playing his very last seasons with many injuries and fitness problems. His performances are no longer at world class level and he will also retire very soon.
Shinning for few seasons isn't enough to level your performance with Messi and Ronaldo. The most challenging aspect of these two players is that both of them were playing at the same thing competing between themselves to be the best. They were sharing Ballon d'or within themselves for more than eleven seasons.
After these players, there are some others like Sancho, Mbappe, Haaland and in most latest years Yamal. Sancho already lost his prime while Mbappe and Haaland will need many more good seasons and titles to reach to just nearly level of Messi and Ronaldo. Yamal looks promising with his great talent and strong mentality but he does not has good professionality like Messi and Ronaldo. It will be a biggest barrier that likely prevent Yamal reaching to his highest level.
I don't know the Sancho that you're talking about because if it's Manchester United Sancho, I don't see anything special in him. Mbappe will shine for long because he's a player with great talents in him. I hope Yamal don't get carried away with distractions so that he can reach his highest level before fading off.