Not sure without seeing the photos of the actual case, but normally, snow exhibits more features in a photo than one expects
Try to use relatively wide aperture (f4 or f5,6 are usually the sweet spots for most lenses in terms of sharpness), and if this aperture requires shutter speed that exceeds what is possible with your camera, then use a neural density filter to reduce exposure without stopping down the f number.
if the snow does not cover the entire frame, it can help, but in this case you should pay attention to exposure and maybe use manual to avoid highlight clipping when automatic adjustment tries to expose better the rocks or vegetation.
In this example at 3000m altitude flown at 120m over the snow the ice surface came out quite well, don't you think so?
https://www.pointbox.xyz/clouds/59ceff26dec41c00108c3ed8