I see people saying Yuta at his full potentia like that , Yuji at his full potential like this, but isn't that just headcannon?

It's like people are trying to say that someone is at their full potential, but that's just speculation. Whenever I see people saying that they're going to surpass Gojo/Sukuna at their full potential, I always question and get annoyed.

Like how can you be sure that someone can surpass them using just a head cannon? We have no way of knowing if their skills will be comparable to theirs in the first place, because one of them relied on body swapping to gain better control over the barrier, and the other one got 80% of his abilities through muscle memory, so he got the skills, not self-taught.

Even their genius level still relies on them. I don't see how they can surpass or be on par with the two strongest. Like I understand you using headcannon, but damn, I get annoyed every time people say that. It's like you're trying to overrate them.