Are you a woman(biological)? If not, you're gonna have a hard time finding an audience. Theoretically there's a market for male vtubers that would appeal to fujos, but if you were interested in that market you'd have to already be posting in the relevant BL communities. And even then, no one has proven such a market exists yet, it's all just theories.
If you are a woman(biological), then you can go at it a few different ways.
1: Have a talent worth using and use it. IE: If you're an artist, start building up some attention for yourself doing art for popular streamers and vtubers
2: Network your way into the social circle of streamers and vtubers so you can siphon their audience
3: Pick a community and pander hard
4: Shill yourself shamelessly and without mercy everywhere you can(Note: This will result in a lot of places banning you. You just have to eat the bans)
5: Some combination of the above
