I have it in use and you don't hear the pump. It is simply important that the radiator is above the pump so that the air bubbles go up. An All In One cooling system has around 10% air in it. For the best performance, Gamer Nexus has made a top video. The title is "Stop Doing It Wrong: How to Kill Your CPU Cooler (AIO Mounting Orientation)".

however, I find that you manually turn down the fan speed in the software to be downloaded. My CPU reaches a maximum of 36 degrees, but I don't game too often or for long and my CPU is still from 2012, emphasis on still. Quieter fans might be better, but that's a topic in itself.

I had enough space in my Cosmos 2 to mount the AIO, but it took me a while to find the right position. My tip, think about where to place the radiator beforehand and mount the radiator first and then the pump. That would have made mounting a little easier for me.

Hi Ancaralu

I just bought the cooler...
Since some parts are still missing, I will wait with the assembly.

If you haven't received an answer by then, I'll get back to you with an evaluation.

Sorry that I can't give you an answer (yet)...