A severely weakened odor could possibly be caused by creating a very low net air pressure with air flow that is way too strong for your needs. You could also be waiting too long to harvest and allowing your trichomes to dry out and fall off, which could be made worse by too much air flow too. As it’s a pretty strange for cannabis to have almost no odor with the higher quality resources available nowadays I suspect it’s not one cause but a series of issues. Low RH, with too much air flow, and late harvesting sounds like what I would do if I wanted to recreate your result.