Shitsuren Shita node Vtuber Hajimetara Toshiue no Onee-san ni Motemashita

Yuki Himemura, who had long harbored feelings for a senpai in his school club, learned that his crush now have a boyfriend. Devastated, he decided to become a VTuber like the one that both he and his senpai admired. He spent his entire savings on the VTuber setup, but when he opened his avatar design, it turned out to be an unexpectedly beautiful 3D model — of a girl!? And that's how he unintentionally started pretending to be a girl online!?

(Source: Young Champion Web, translated)