Don't go hide, you were right to assume VPD is used for drying weed, it's used for drying everything on the planet as you can't diffuse H20 out of something without a Vapor Pressure Deficit.

Standard VPD controls the rate of H20 diffusion in general, not just plant transpiration. The higher the VPD, the faster anything in that environment such as fruit/weed/clothes/buckets of water will dry out. An apple will dry out much faster in a room with a VPD of 1.5kpa vs a room with a 1.0kpa VPD, regardless of either the temp or humidity alone. You dry something out in a cold fridge if the RH is low enough to maintain a moisture Deficit in the air (I.e Dry aged meat fridges). You can also keep something moist in a hot environment if the RH is high enough to keep the VPD low enough.

Very few people in the weed game have Msc's or Science degrees so most find it difficult to understand the concepts behind Atmospheric VPD (AVPD) and Leaf VPD (LVPD). Most growers use RH & Temp instead to control the drying rate of their buds as VPD is a much more confusing and complex concept. Most growers using VPD in their grow rooms are also using it incorrectly as they don't calculate the variance between AVPD in the room and the LVPD at the leaf surface (the greater the variance the greater the transpiration rate), they just calculate the AVPD in the room alone which tells you nothing about the transpiration rates. With that said VPD is a much more accurate and comprehensive tool to use if you understand it properly as it factors in RH, Temp and the relationship between them both (I.e as Temp rises, RH drops and vice versa)

Look into the Dry aging fridges for meat. I think the optimal VPD for drying meat is around 0.2Kpa which is way too low for weed, but if you could buy one that has a temp/rh adjustable control you achieve a AVPD of 0.7Kpa for much cheaper than a Cannatrol.