I cruised the Dream in September for a 4 night sailing. Palo brunch as sold out when I was online booking (Silver at the time, will be Gold for next cruise in September 2020, if that matters at all due to booking windows), so I went to Enchanted Garden after embarkation day lunch to try and snag a reservation. A rep. from Remy was filling in at the Palo table, and he was only able to put me on a waitlist as there was "no availability" at that time and had to wait to see if any cancellations would occur (to his credit it was crazy down there with people and all sorts of requests, he may have been slightly overwhelmed and I do not blame him!).
However, when I went to Palo for dinner the first night and spoke to the actual rep. at the host/hostess station at Palo's entrance, she was able to get me a reservation for brunch right away as there was much availability. So it all depends I guess. If I did not ask about the brunch again at dinner that night, I may have just remained on the waitlist and possibly would not have gotten to experience brunch at all. Brunch was excellent but I do prefer the dinner service at Palo more.