go with nemu at least you could make a slow-paced development and can focus on plot and other things while giving the mc and nemu a chance to develop their affection while having mayuri and the mc a relationship akin to that of "father in law against his son in law" after all mayuri will think that the mc would make nemu inefficient while having nemu the love interest of the mc would definitely have nemu experience character development and break Mayuri's perception that nemu is his "perfect" creation opposed to him only realizing it in TYBW.
Einlion:Kind of.
Sorouko:Did he follow through?? I haven’t touched it yet and I’m wait to see if it’s true