I use plastic tubs similar to this with desiccant to protect my 3d print media from Spring time humidity here on the east coast. I've found they help protect my ABS during storage... might help you with your cards?
https://www.amazon.com/IRIS-Weathert...s%2C110&sr=8-8
Also... asking a remediation expert to assess for mold and fungi is a bit like asking a fox to watch your chickens. If you think that you may have a real health issue, I suggest an indoor air quality inspection first (3rd party consultant) and go from there. Remediation outfits will always find a problem to get the work even if it's not necessarily needed imo.