I was rejected by Fashionable BigCo X and Y but then eventually got a job at Fashionable BigCo Z
Which is great, it really is, but not really all that interesting (sorry!). You've only been rejected in a very narrow sense. Everyone has an off day, or off interviews. You were actually accepted by the mainstream, eventually. It's like saying you were only accepted to 2 of the 5 world class universities you applied to. In what sense have you suffered rejection?
I was hoping for more of this variety:
I was rejected by Fashionable BigCo X and Y and Z. That path was obviously not going to work out for me. But I at least knew my own value. So, undeterred, I instead did awesome thing #
There are a couple like that. That's interesting. Someone who holds their confidence and actually outperforms others' expectations, despite lacking conventional sources of validation.