^There is 'Girl Meets Girl', where the MC is in a love triangle between two girls after changing genders. There is also 'Tensei Kyuuketsuki-san wa Ohirune ga Shitai', which is about a lazy, sleep-obsessed boy reincarnated as a still sleep-obsessed vampire girl. However, the chapters released so far have not delved very deep into the yuri side yet.
But, I agree with you... most gender swap stories are either het, or tease between het and yuri, or they become yuri but the protagonist changes back to male at the end.