>>8704488She has by far the biggest case of imposter syndrome in all of Hololive.
Imagine if you will, you sign up thinking that it'll just be small to medium bump up in audience size from what you're used to, with people to stream alongside and someone to help keep your laziness in check in the form of a manager.
Oops, you've now got TENS of THOUSANDS of people watching you debut due to a meme and a dream. You're an absolute nervous wreak, but manage to nail it with the song you've been practicing for WEEKS.
Oops, you're now the 1st v-tuber to hit 1 mill subs starting from scratch, passing all your Senpai and now all you can read about are NUMBERS NUMBERS NUMBERS NUMBERS ALL THE NUMBERS NUMBERS NUMBERS NUMBERS.
The mere mention of numbers probably drives her mad, but she also knows she has to live up to it even more now that she has a set of Kouhai to guide and show that she didn't get here off of JUST luck.
TL;DR - 1million and 3 million milestones just reinforce her imposter syndrome when all she wanted was a step up and some friends.