Paris and Liguiria in 12 days

Hi! My then wife and I will be going to Europe for the first time next August. We're going to arrive in Paris on a Tuesday, probably midday and fly home the Saturday after next. Maybe the Sunday. So 11-12 nights. We would like a few days of our time in Italy to be slow paced and relaxing.

I have read that Paris for a first timer should be 5 days. So probably want to use the Sunday as a travel day.

My question is: how many days does it take to see the area around Santa Margherita Liguire? Should I make our relax part of the vacation there, or should I continue down to say Naples or Rome where it's easy to fly home from?

I suppose my fear is that Instagram is making Santa Margherita Liguire seem more interesting than it is.

Thank you!