
to me, megumi being head of the zenin clan means he can just make maki the next one no? or at least up her ranking - assuming she survives

Yes definitely. But she'd probably feels like its a consolation prize or participation trophy. Since her goal is to prove herself and earn the title that way. Megumi casually passing rank to her would feel cheap and anticlimactic.
Also it will hurt her to know that Megumi lucked into her dream job and it will literally mean nothing to him. yikes.
that mf PACKIN