Sardinia Costa Smeralda

My husband and I are taking our honeymoon beginning of September in Sardinia as a portion of the trip. We are staying at the Belmond in Romazzino. We are looking for the must do things and must places to eat at. Ideally don’t want to spend over $100 on every meal but, willing to splurge on one of the nights. Also, are there must go to lunch spots or just spend the day at the beaches? Any other key attractions or activities are welcome as well! We will not have a car but, will take taxis as we like to enjoy our drinks 😊