If Rentaro can't fix this, I'm expecting the synchronization goes through and Nano spends the next 20 years creating time travel. Then instead of going back and fixing her timeline, she goes back to the past of the Superior Nano timeline and syncs it with the "main" world, so Alt Nano falls in love with Alt Rentaro and never starts the dimension hopping nonsense (which retroactively means the main timeline was never touched and everything goes back to normal).
And the moral will be that "main" Nano ended up accomplishing more than the Efficent Nano, since emotions pushed her further.