I just wanted to add a word of warning. We just did a shirt 4 night cruise and while I booked 2 nights ahead of time on the app, I thought, oh well I will get the Concierge to help with the first night (first night specialty is no longer free on short voyages either) and the last night. All restaurants were fully booked. He even called the manager of Crown grill for us, Nothing. We finally, at the last minute, got into Sabatinis the first night, and not until 9 the last night in Crown Grill. Lesson learned book ahead for the times you want and get the adjustment later (if it doesn't auto adjust)
The restaurants weren't full either I think they are short staffed and less tables are being offered which adds to the availability problem.