your speakers can be set to -6dB for the input sensitivity, so already you're down from 4.4v to 2,2V with such setting even balanced. that gets you closer to the max for the speaker's internal amp and any further attenuation (digital or with a volume controller) will be able to get you out of clipping risks. I believe the issue is mostly about getting you to a comfortable listening level, and not much else. as with a lot of this hobby, the line between overthinking and high end concerns can be very thin.
about a volume knob changing the levels too fast and making it annoying to use, that's a problem any designer has to think about. if you make a wide attenuation range, it still has to fit within one turn of the knob and your listening preference will of course be hard to get just right. we all would rather have something already in the area of our listening preference and with a much smoother/smaller range of attenuation so we can make big moves with smaller impacts. but that means getting the initial gain just right, which is not really your case here. you're already struggling to get below the loudest output the speakers can handle. that's going to be loud(I'm captain obvious
). and a default volume controller will tend be the kind with a pretty wide range of attenuation because the guy making it doesn't know what we're going to use it with so he'll ensure a wide range just in case. you have to play with the cards you're given. TBH I personally wouldn't have bought this DAC and those speakers to go together in the first place, so I see your situation as solving a problem instead of thinking about what's the very best thing there is for elite audio.
I have active speakers and I feed them with a cheap Scarlet 2I2. really nothing to be impressed with, but the gain was fine from the start, and the output has a volume knob, the result is simply practical. if I was in your situation I would use a passive volume controller if I liked both gears a lot, or I'd get rid of one of the gears and get something more practical. as you're aware you have more options, like adding an amplifier in the chain, but I personally wouldn't bother with that in this specific context. an amp to reduce the volume is something I did myself for IEMs once, and if I had to do that again, I'd just get an inline volume thingy or get rid of the annoying IEMs.