Some additional thoughts, as we were on the same sailing:
Our PAT was 10:45. We arrived on time and got through testing and on to the ship about 12. Apparently they were having testing issues if you showed up much later. There were people with a 12 Noon PAT who arrived on time and didn't get on board until nearly 3:30 PM! They said there was some issues with the testing provider. I would encourage others to get the earliest PAT available.
Sailing out of Miami was ROUGH. We live in Orlando and there was a cold front just leaving FL that apparently stirred up the water quite a bit. The first night was a wash for the most part. We left in the middle of dinner because we were all feeling so icky. Thankfully the rest of the trip was smooth. We pulled away from the dock at 5:15 and made it out of the channel around 5:30/5:40.
The adult beach on Castaway (Serenity Bay) was destroyed again by the waves leaving that sand wall where the chairs should be closest to the bar/bathrooms/buffet area. The water was also chock full of seaweed. Based on all 4 ships calling on the island, I wouldn't be surprised if it stays like that for a long time.
They were just finishing up the gingerbread house itself while we were leaving the ship but hadn't done any decoration on it yet. The whole atrium smelled of gingerbread as we were getting off the ship. Someone asked one of the pastry chefs building the house and they said it would be done halfway through the next sailing.
We were RRLLA for our dining rotation. The second seating was a ghost town with only about 20 tables total. Pirate night was on the 3rd night. They have made a few changes to the Pirate night menu (they added a delicious Osso Bucco entree) and moved a few things around. Per our server, they updated the menu two weeks prior. Rapunzel's was possibly the biggest change/disappointment from previous sailings on the Magic with the show being so heavily modified, I question why they still did it. There was Flynn, Rapunzel, Hook hand and Attilla and that was it. No live music either. Food quality was the best we had ever seen on board the Magic.
The clubs were decently busy throughout the sailing. At one point during a live piano show in Keys, they were turning people away. All seats were filled in the venue with no social distancing which was totally fine. (Thanks Covid testing!) There was a decent amount of spacing anyway between seats. The most empty of them all was O'Gills. Unless there was trivia going on the pub was a ghost town.
There were plenty of activities on the app (Trivia, family games, etc) throughout the cruise. We didn't participate in much of anything. We spent most of our time at the pool/hot tubs.
We did see Eternals on board which was enjoyable. The movie theater was packed by the time the movie started. I would encourage those who want to see the movie to get there a bit early. There were no snacks/drinks/popcorn available yet sadly outside the theater.
Christmas time offerings were sparse compared to previous Merrytime Sailings we have done. No Show in the atrium. They did have the characters in their christmas attire and they did have carolers in the atrium a few times throughout each day. Otherwise it was just the Christmas decorations pulling double duty throughout the ship. We didn't see gingerbread decorating like past years. They did still have the storytime and meet and greets with Santa and Ms Claus.
No show the first night, we had Twice Charmed (night 2), then Tangled (night 3), Eternals all day (day 4), then Disney Dreams (night 5). Both Twice Charmed and Tangled were phenomenal. Didn't bother with Dreams since we had seen it previously but others in our party went and loved it.
A lot of this has already been covered no doubt. Happy to answer questions if needed also.