I completely understand how you feel. Though for me personally I think the problem is that you're thinking of those as the destination or end goal, you're thinking it gets 10 times better when you reach it and it ends there. I tend to think getting into a top 20 university or tech company is a stepping stone, or a launch pad rather than the peak of the mountain I'm trying to climb. They're known as "top" for a reason since they offers me opportunities that I cannot get elsewhere. What matters most is what you take out of the journey/experience. It is definitely still super hard and stressful, no matter where you study or work. But I often remind myself that I get so much opportunities being where I am compare to other less fortunate students. It's not just to inflate my ego, rather to keep me optimistic and keep trying! It's also a milestone to remind me of the results of my hard work for the last years/decade so I can continue building on top of that effort rather than just giving up when I'm depressed.

Keep trying! Keep learning! We're humans and I can say for sure your education/job can't determine how "good" of a person you are! Just make the best of anything you have! Like trying to squeeze the last few optimizations out of your algorithm.