Mech E is not an easy admit and if you think that I have a bridge to sell you. People should apply for the majors they are interested in. That said, the OP applied for MCB not Mech E, not CS, not EECS.
More pertinently, there are plenty of highly accomplished applicants who don’t get in during the early admits (or) get into Berkeley at all but end up in even more “prestigious” institutions. Here’s just one example of a poster from the 22 cycle who got into MIT and Caltech but was waitlisted at UC Santa Cruz.
I know nothing I say here is going to calm anyone disappointed right now but I promise you will look at this whole phase later and wonder why you were so worked up.