For a while, I just had a link to this site. However, friends have pointed out to me that it's not an entirely seamless site. In short, anime culture has a problem with over-sexualization and objectification of women. If in doubt, you can read the short article. You can also remember the trend in late 2017, when people, for fun on the Internet of any kind, started making versions of them as anime women, an example might be \earth-chan\ but there's also a whole wiki, documenting it. Symptomatically for the whole culture, however, the trend did not remain for the creation of anime characters; of course, the characters were illustrated with lewd versions.
I don't think there's anything fundamentally wrong with creating random avatars, it's a funny concept, which is why I left this link here. But if they're exclusively girls, it's unfortunately got a bad ring to it in this context, sometimes even pedophilic. So be warned that the generator itself is not NSFW, but by using it you can (even unconsciously) contribute to an unhealthy trend that puts women in an inferior position. I hope it is clear that it is not a good idea to reduce women to mere objects of male sexual desire. This is a real, socially occurring problem that is already making life harder for women.