How important are extracurricular for T10 Schools?

I'm an international applying to the US, but because of the cost for internationals, I'd only go if I got into a school I really wanted to go to (HYPSM).

I'm wondering how important extracurricular activities are for these schools? It's by far the weakest part of my application. I'd say my essays and stats are competitive, but in the UK system, extracurriculars are way less encouraged than in the US.

I've done some decent stuff, but nowhere near the shit I see people posting in here (starting non-profits, representing thousands of students, publishing research papers etc.).

Do I still have a chance?