From the 'boyfriend' remark, it seems like despite not having switched back, they're keeping with their original gender identity, which could still cause a lot of feelings of dysphoria in the future. not sure how I feel about that, but as long as they're ok with it I guess?
Thank you for translating^^
So my guess would be that they switched back when yui made that desperate plead. My argument for that would be that the yuuta body called yui body his boyfriend, so yui in yuutas body called yuuta in yuis body her boyfriend. Also how Kazuma laughs at the question if he liked yui and weird girl behavior towards him(forgot her name). Until the epilogue gets translated and proves otherwise I will go with this assumption.
Though I had hoped to get a more... satisfying? longer ending, I really liked it. But the epilogue will come and maybe we will get a more satisfying end there.