You may have considered this already, but mowing lawns would be a great essay! Lots to talk about class/race, which seems to be one of your interests (given your speech and position at your school’s BSA and your username). Also reveals a lot about your character that you are able to find some zen in the midst of all those lawn clippings… haha. (I hate yard work!)
As far as ECs, while it is great that you do a lot of stuff (as long as you find it rewarding), you may want to streamline a bit when it comes to your apps. I would definitely “brand” you as a socially-conscious/“woke” STEM dude. Highlight the ECs in those areas above the others. Business and Mock Trial – while worthwhile – may “muddy” your application unless you can find a thread to unite them with the above. I mean, this could easily be done if you’re into social justice law, etc… If you don’t have a unifying thread OR a significant interest, definitely put these on your app, but maybe further down and don’t necessarily elaborate on them in your essays.
For better or worse, I think that the kids who consistently are most likely to “win the lottery” of ultra-elite college admissions are the ones who can coherently package themselves and their story. It doesn’t mean that you don’t pursue any and all interests, but you don’t necessarily have to bring all of these to your app. If you can do that successfully, Columbia is a REAL POSSIBILITY which is really the best anyone can say (there is some merit to the lottery analogy, after all). If you apply to a bevy of similarly-elite schools, you’ll very likely be admitted to at least one (this isn’t to say that you should not also apply to a range of targets and safeties). Good luck!