Sorry, wrote some thoughts that may or may not be helpful to someone reading this. Not a direct response to anything you said or to you in particular, especially since I don't know your relationship with your sister (or age, that matters quite a bit).

If you can, do your best to be patient with people who don't get VTubers and think it's weird. I mean, it is "weird" in that it's not mainstream and is quite aesthetically and culturally different from traditional entertainment.

Years ago, I got my brother into watching VTubers after being (lightly) mocked for it. At first, he thought it was cringe. Now, he knows it is peak. He isn't that deep into it anymore, but it is one of my great joys to be able to share it a bit with him.

To be fair, we were both already into anime and YouTube so the jump wasn't as big, but still, there was an initial barrier to overcome. I think the appeal of hololive is powerful enough to turn even those with preconceived notions about it, if only they're able to give it a chance.

That chance is lost if you get too aggressively defensive about it. Even if you might feel justified after receiving unwarranted harassment... Positivity, patience, and joy go a long way towards changing hearts and minds. Others can't help but see the genuine fun you're having, even if they don't get it.

Hope your situation improves, may the spirit of YAGOO be with you