Momo is in no position to act high and mighty because he's allied with Luffy. Listen, Luffy and SH will leave. Wano is basically wide open, one Admiral can take over the country. He has to make some sacrifices. Maybe Oda will parallel Dressrosa where those little fuckers stalled Fujitora.
Momo will try to sort out things with Aramaki while Scabbards try to make SH's and others leave or shit?
Could go different ways:
Momo gives in to Ryokugyu, and let's him search the country only to find out they already left, therefore he leaves Wano
Momo somehow someway talks through that bull skull to convince for a deal to ally with the WG, making him forget of Luffy? Or again he gets stalled that way long enough so he leaves
Momondrives him out of Wano, accidentally firing an uncontrollably strong blast breath that flings Ryokugyu (off guard) far away. With him momentarily away, Yamato is officially in the crew and tells them to leave so Wano wont be under attack after they just tasted freedom, Luffy and others leave shortly after, with Ryokugyu in a hot pursuit outside Wano.
Or a last option some mix of all above.