How much will a bad 1st semester junior year hurt me for MIT/Stanford/Princeton/Caltech/Cal?

Is there a local college counselor that you know has success with admissions to your desired top schools and for which your parents would pay the consulting fees?

Honestly, you seem unable to benefit from the advice given here, so your best bet might be contracting with a consultant. You may be more inclined to listen to advice when you are paying for it.

I don’t think it’s necessary for most people to pay thousands of dollars for college admissions consulting, but in your case I think it could be the difference between success and disaster (defined by your concept of what admissions outcomes are acceptable.) With some adjustments to your direction, choosing ECs wisely and focusing on results, you might still be able to get into the schools you deem worthy and maybe a consultant can give you some guidance that you seem unable to hear free of charge.

FWIW, my son was just admitted to a top 5 school and his grades and test scores were similar to yours. But his ECs and targeting of the colleges were IMO what get him admitted. No, I don’t think the additional explanation you gave of your ECs helped your case any; if anything, your explanation showed you aren’t “getting it”. You still have time to get it and turn this around, but obviously spending time on cc where you either don’t listen to or don’t understand the advice isn’t helping. That’s why I think you should start looking for other help such as a paid college admissions counselor.