or if it's just "abs" or "nylon" that you buy and hope for the best.
Yep, that pretty much sums it up. No real material spec sheets whatever, mostly boastful claims about how wonderful it is....

"Humidity controls" are improper for drying and long term storage at elevated temperatures is one of the worst possible things you can do to a resin... yet I see a lot of people doing exactly that
I agree that raised temperature is not the best for the filament. It is also my opinion that drying gels are of little use too. I have a vaccuum oven for drying which goes down to 50-100 mbar. At 60-70C that is below boiling point of water.

Do you have experience with respect to vaccuum drying and how it may affect the filament?