I was recently on Carnival, and they totally changed their procedures. They now have a totally separate menu page for GF.
I am an eggs benny fanatic, and I ate them every single morning but with different sides. They made it on their own gluten free bread which was some of the best I have had.
After dinner, I would order what I wanted for breakfast, and also dinner the following day. I didn't have to do this, I could have just ordered, but the pre-order lets the kitchen plan my food out and it arrives much faster.
The GF menu is right there in the app, and I liked that I had plenty of time to consider it.
Just providing this for some contrast, as it looks like no two lines handle things exactly the same.
This is kind of a trial run for how I'm going to document eating GF on cruise lines I'm trying. Next up is Regent, then Oceania.