Worth noting that resonance also plays a part in how fans and pumps sound across or even outside the same room. Don't know what case you have or what material the system sits on but mine is in a Phanteks Enthoo Evolv with the glass side panels and rubber feet which is on a plank of wood also on felt pad feet on laminate flooring so there's quite a bit of material to absorb resonance. If your case is sat on a desk or hard floor just as is then maybe the resonance frequency is just the right amount to be noticeable to your ears and as such not acceptable?
I've returned AIOs before or sold them on because the noise just wasn't for me whereas others in reviews had no issues with noise so from that experience it was clear to me that resonance played a part in how any cooling system does sound which is also why now I've been looking at a way to set a custom pump curve for my H115i so I can change the frequency so it's less audible with these extra quiet fans but I may just wait until a major upgrade and just change the core stuff all at once next year now.