Depends on the AIO. The asetek pumps used by some Corsair's and nzxt and fractal design are much quieter generally than the square Coolit pumps on the other Corsair's and other brands. Some of the custom 'in house' manufactured designs like used by deepcool etc are hit/miss as to volume. The pump on my nzxt Kraken was dead silent, even with the case cover off. Almost had to stick my head into the pc, with the pump running max speed (the Krakens are variable speed according to need) to hear the slight hum.
But as stated, noise is a personal thing, I generally keep the pc at a low enough volume to hear the wife yelling for me from downstairs, so a loud pc distracts from what little volume I can get. The larger fans on the 280mm spin slower for comparable airflow from a 240mm, so are quieter, the larger surface area of the 280mm affords better efficiency than a 240mm, so the fans spin slower still. Bonus. My daughter does everything by headphone, so could care less what volume the pc fans run.
At idle, the pc was so quiet, I had to train my wife to look for the power button led light first, because she couldn't hear it (unlike her pc at work) so assumed it was off.
Favorite aircooler for Ryzens is the beQuiet Dark Rock TF. It's not that tall as it's a down-draft style cooler, but has comparable efficiency and performance to a NH-D15S, while costing less, looking better and having airflow benefits the towers lack.