Thank you so much for replying!
I use Cypress Mulch, and I do complete substrate change every 4-6 weeks. I found this to bring the humidity up for a short amount of time. I'm very open to switching substrates if that's what you're recommending! Also, I regularly spray down my tank, I have an exo terra glass tank with the metal mesh wiring, which is covered/sealed right now. But I check on my hygrometer around every hour, or when I walk by and shows it to be much lower than wanted. (I'm on summer break atm). And I spray that and I soak the moss in water and set it on his hot hide.