Would generally be true one would think, but like the OP, we found Majestic Princess overrun with kids for both our 2 week cruises the previous year around Xmas, with no where to relax and chill (holywood pool club used to be adults only at one point when we originally sailed on her, but not now) so opted for same cruise last Xmas 5 weeks ago on HAL. Very different experience. While I prefer the Royal class ships to the Vista class, there was next to no kids on HAL for the same cruise at the same time. So very much enjoyed my holiday alot more...
Have been rotating around other lines again, and also had a more relaxing time without kids overrunning every square inch.
Will probably stick to the other Royal ships that have a sanctuary and outdoor adults pool So have somewhere to go when I need it. But a shame as I liked the adults only indoor pool on Majestic when it was a thing.