Low impedance headphones are too loud, even on minimum volume.

I recently purchased a set of low impedance headphones (around about 20Ω). These work great with my iPhone XS, but on my iPad Air 3 it is far too loud, even on minimum volume. I can only assume this is due to the iPad having a more powerful amp built-in, but even after activating and maxing out ‘reduce loud noises’ in Settings>Sounds, the lowest available setting is just barely tolerable, but anything lower causes the music/media to abruptly cut out. Is there any other way to reduce the volume range of my iPad with these headphones, or should I start looking for some higher impedance headphones? If so, is there a suggested Ω range I should specifically keep an eye out for?