Alcaraz is top 10 player on fast playing HC, but not a top 3-4 player. He's still great, but comparatively he's more on the level of a Fritz, or even a Rublev - great player who can still occasionally lose to the Machacs, Humberts, etc. That's his limit right now. If you can speed him up, rush him, he can tilt
This in part also explains why his HC H2H with Sinner looks so good - most of the matches came on medium to slow playing HC(Indian Wells x2, Beijing x2, USO '22), where he tends to do much better. This AO he lost to Djokovic, otherwise I reckon he beats Zverev. He also just gets an emotional boost against Sinner because he's his benchmark. The one he measures himself against, so he tends to play freer, looser. Djokovic is just too huge a figure instead, Carlos tends to let Nole get into his head
I really like Shelton, and I mean really like. I like his talent, I like his attitude, I like the clear improvements he's already made on return, I like his spirit, I like his personality, and I like his tennis. Should probably work on getting to the net more often - like all the time actually - but he's potentially one of the guys who could disrupt the Sincaraz duopoly in the coming years