>Needless to say, I feel horrible.

Is there a reason you want to get into those companies so badly? I personally don't practice leetcode, because my ROI on those types of problems is not really great, and I'd rather do things that I find to be more interesting with the time. This does mean that, when I interview, sometimes interviewers treat me like a child for not being able to reach optimal solutions for problems they know to be well known or simple. But I'm ok with that, because tech is an absolutely huge field, and there are companies out there that better fit me.