Should I move to an american school for Junior year?

Im currently a sophmore and have been attending a british school my whole life, but I’m planning on going to university in the US. My school is quite rigorous and the exams are very stressful, I will do a couple extracurriculars next year eg. music ensemble, research project, math club and possibly a leadership position.

But I’ve been reading about college admissions in the US and they value extracurriculars way more than UK universities who barely take them into consideration unless theyre related to your degree. In the US they’re more focused on extracurriculars and essays and obviously the SAT. Theres this good american school near where I live which I could attend. They have many extracurriculars as well as sports and stuff like that and offer AP classes as well. However, the school is fairly new whereas my current school is more established.
My current school sends a couple students to prestigious US universities like MIT and gets pretty good grades overall. I’m worried that since I dont have the same extracurriculars as american high school students this will put me at a disadvantage. So do you think its a good idea to move schools for junior year?

Are you in year 10 right now?
What grades did you get for GCSEs (list, with subjects) so far and what are you predicted for this year?
What ALevels would you take?
If going to the US school, what would you take Junior and Senior year?
Where do you rank at your current school (are you top 10%?)
An issue is that for top US schools you don’t just need to be enrolled in activities - just a couple is fine but high achievement in them matters. Which school would allow you to be both top ranked and achieve at a high level in 1-2 activities you love?