In 21w06a, clouds were shifted upwards from y=128 to y=192. While widely regarded as an integral change from the update by the community, according to MCPE-119836, this new cloud height is not actually intentional design and should be moved back to y=128 for parity.
Having cloud height be a customizable setting through world/dimension data might be a better option.
I don't think the clouds inside the high mountains from 1.17 will look natural at such a low height. Imagine-you are digging in a mine on a high mountain, and then a huge cloud appears from the wall...