It doesn't have to be loud!
I literally vacuumed under my sleeping girlfriend (and it's not like she sleeps that deeply on the sofa, it just wasn't louder than the running TV). The loudest part is, unless you turn it to max power, the scraping of the thing over the floor. Compare that to the upstairs neighbours, who we barely hear except when they vacuum.
My mom's first reaction, when I excitedly told her, was "yeah but those don't have any power". Not sure, I've used a bunch of vacuum cleaners over the years (old or second-hand in student rooms, newer stuff at my parents' house) and this one doesn't do any better or worse than others. The EU also reduced the max power of new vacuum cleaners, apparently they're overspec'd for the job and people just buy what they think will get them done faster I guess? Haven't read up on it, I just remember reading that the max power allowance went down as of some recent year. Perhaps the loudness is subconsciously a proxy for performance since an ordinary person can hardly measure suction directly?
In the EU, appliances have a score card. In the case of vacuum cleaners it contains things like how well it vacuums, how much dust comes back out while vacuuming, how loud it is, how much power it uses, and another stat or two that I don't remember. They're all roughly the same (I just walked through the store from vacuum to vacuum for each stat to see what the best is you can get per price category) in pretty much every stat except noise level and power usage. In those two categories you can win a bunch for virtually no extra money and I'm super happy with it.