Planning ECs for Junior Year - are 100hr weeks normal?

Yes, ^ that. Choices.
I’m not here to tear you down. Remember, I do see you’re aware and trying to juggle. But there are points in our lives where we face tough decisions. How we set our path forward is as important as the pleasures of the present. It’s important to be informed as well as possible, call it, “Eyes wide open.” Not go on assumptions or hearsay.

It’s different when one is thinking “top 20.” If you have happy, affordable (true) safeties, it can be much easier.

I have my own experience in this arena, working for a competitive U. And I’m a parent. When D2, a fine and strong musician, asked about dropping one impressive orchestra, (roughly 10 hours per week plus practice,) I gave her much the same advice and the decision was entirely hers.

A kid doesn’t, imo/ime, need to do it all. That’s not what gets you into a T20.