That’s a lotta moisture. I recommend getting a water mister like this: Beautify Beauties Flairosol Hair... https://www.amazon.com/dp/B0762GP85D?ref=ppx_pop_mob_ap_share
Hold far above and let the mist fall. You only need an amount of water that will provide tiniest big of sparkle when shines on with a light.
I normally use rye grain.
Here's what I get.
It's excellent quality.
https://www.amazon.com/Homestead-Harvest-Rye-Grain-Non-GMO/dp/B08PDS4LQW/ref=sr_1_1?keywords=Ernst%2Bgrain%2Band%2Blivestock%2Brye&qid=1658972408&sr=8-1&th=1
What's GPT? My brain isn't working right at the moment. lol
Probably not ruined. Dryness is the concern for safety and storage. Cracker dry is what you want, within 24 hours is great. Heat is what would affect potency. Psilocybin starts to degrade around 180f. I dry on wire racks over reusable desiccant in a sealed plastic container until crispy, then jar up.
Here is a grow tent that you could put down there.
I also know where to get a cheap laminar flow hood (around $400) if you need.
I'm building a mushroom cultivation business as well.
I use mason jars and mostly 6 quart bins to minimize damage from contam though I hardly have any.
Your basement should work really well as long as you set up proper air filtration. Find a HEPA fan to circulate air maybe.
I picked this one up, I think 90 second recommended it. I might try it in fridge like you have, it isn’t holding temp without insulation ie in a large tote box in a cool area.
VIVOSUN 10"x20.75" Seedling Heat... https://www.amazon.com/dp/B016MKY7C8?ref=ppx_pop_mob_ap_share
I got it off Amazon. It seemed like a good way to try mushroom growing. https://www.amazon.com/Mini-All-One-Mushroom-Grow/dp/B08J2GFTPS/ref=sr_1_4?crid=329AE88IGDZDE&keywords=Mushroom+grow+bag&qid=1647986445&s=lawn-garden&sprefix=mushroom+grow+bag%2Clawngarden%2C100&sr=1-4
It greatly depends on where you bought it, the type of spores & the number of spores they added to the syringe. If you shake the syringe vigorously for a few minutes you should be able to see some. However, if you're worried about it then in the future you can buy a $13 pocket microscope to see how many are in there...
https://www.amazon.com/dp/B00LAX52IQ?psc=1&ref=ppx_yo2_dt_b_product_details