I'm gonna be super honest with you:
For most people, you run into someone critiquing your work for the first time and noticing things you didn't do perfectly once in a while, and you have time to think on it and learn and grow. While your audience is still smaller, you get someone telling you that your character's action was unrealistic, and while that's perhaps true you can get over that one comment and make your character writing better and better as the story goes. As time goes on you get more and more comments, and after a year or two of this you've learned how to process that kind of criticism and determine what's helpful and what's not.
But this didn't happen with you. You've been thrust into an unnatural situation, been asked to immediately be able to handle something you weren't trained for the way everyone else was, and it's natural and normal and okay to feel overwhelmed by that.
I think if you are able to find ways to come to terms with the visibility you now have, that's really good and the ideal scenario! But I also understand that it's really hard. If you end up having to step back from your comic for a bit because it's causing you too much stress or burning you out so much that it's not enjoyable anymore -- your health comes first.
The first thing that came to mind for me when reading your post was actually Hanna Is Not A Boy's Name -- a comic that got a sudden whirlwind of popularity back in the early 2000s that became such a frighteningly overwhelming, entitled fanbase that the creator had to step away -- but now, Tess Stone is back again and going strong with his new comic. It's not ungrateful or wasteful to need some space -- don't feel like you HAVE to suck it up if it's more than you can handle right away, because it's possible to step away and come back later!!
That said, here's a note about "brutal honesty."
People can be honest, and still not be correct. Someone might say "this art style sucks" and they're being honest -- they don't like the art style and they think it's bad -- but other people DO like the art style, so it would be more accurate for that critic to say "I don't like this art style." It's possible for one person to wholly love a thing that someone else wholly hates, and both of them are being completely, totally honest.
The problem is that people tend to be a little entitled -- to assume, without realising it, that everything on the internet is created for them, and therefore if they have a problem with a piece of media (a) the creator will want to know and (b) it's a universal problem that should be fixed....... when sometimes neither of those things are true.
It's okay to ignore criticism. It's okay to ignore well-meaning criticism. It's okay to ignore criticism that has merit. It's okay to grow at your own pace!!!