@PurpleBandito I am going to interpret your post as that of a student who is truly trying to figure out the next steps rather than as a “humblebrag” post.
To be in the USAMO qualifier is a pretty big deal. To get the grades you have at TJ is also an accomplishment. Lots of students study their brains out and they’re not anywhere at this level.
Do you enjoy the math at that level? Is it a passion? That’s what you need to ask yourself. Training for the AMC competitions is like training for a high level sport. However no one ever interprets that as a “grind” and most people clearly acknowledge athletic talent. I am a math prof and my own kid did some AMC 10 stuff , but it was clear that to get further, one needs a certain mathematical bent. So it’s not something he pursued.
So reframe your thinking in terms of intellectual curiosity rather than as a stereotype of the typical Asian kid. That may help in crafting your essays. If you have no other ECs , at least try and do some volunteering over the summer. The idea of moving back to your home school for senior year may look like a ploy to game the system. AOs will still see the transcript from TJ.
You do need to acknowledge that the reach schools are that for everyone. But the candidate who can introspect and make this a meaningful journey will likely be in a better position than a student who just wants to rest on their stats.