Hmmmm, for drying plants I recall days spent in the hayfields. A bright summer day with dry humidity and a bit of Okla breezes made the best, brightest non moldy plants.
I don't do bunches, dehydrators, or ovens. If the leaves don't crumble you possibly dont have them dry enough, or the natural oils are heavy. I wash, pat dry, and depending on the herb, either string them up or lay them on a paper towel with the cut end higher than the growing end- these are tucked under a shelf to protect them from cat. Dust is kept off because there is a fan circulating air conditiond air around the room.
The dog brought me his frisbee and I gathered Hilltop oregano as it began to rain...
Rosemary (prostate) ready to strip
Lesbos or Sweet Aussie basil drying, I wish it were brighter, but this will work and it is about ready to strip
I have Tuscan Blue rosemary, peppermint, French thyme, and more prostate rosemary - the large leaf stuff needs more work to crumble