If its either broad or russet mites and the plants are suffering that noticeably you would see damage that is very clearly caused by them. Can you provide some close ups of the plants for us? Focus on areas of greater damage so we can get a look at the condition of the foliage. Be on the lookout for the following signs for mite damage:
Note the brownish tint and the speckling on the leaves that almost look like trichomes. Sign of russet mite damage, observe closely with a 60-100x scope.
Note the warped condition of the foliage, that kind of twisting and shriveling is indicative of a broad mite infestation and your cannabis plant will look the same.
Both of those insects are difficult to see with the naked eye until the infestation has spread significantly. If you don’t see anything like this than you’re more likely looking at some form of disease.