Asian Tramp Snail Vivarium Questions

Hi! In 2018 I found an Asian Trampsnail on a houseplant I bought. I didn't want to release him because they're invasive, so I've been keeping him. I name him Hamish. He's in a 3 gallon terrarium with a hygrometer, thermometer, uvb frog lamp, tiny adjustable heating pad, coconut coir, a pothos, sphagnum moss, a hide, a dish of water and a dish for food.

Recently I replaced his sphagnum moss again and it bloomed with a white fuzzy fungus/mold, and now it smells! I'm going to take out all the moss and rinse it well and maybe blanch it in hot water. Hamish seems to be doing fine, though.

I'm really curious about bioactive vivariums. I think springtails could help a lot with keeping fungus and the like in check. But I don't even know what questions to ask!

What is the tank maintenance like in a bioactive vivarium?

Asian tramp snails supposedly only live for 2 or 3 years in the wild. If Hamish is getting old, what can I do with the springtails and isopods after he passes?

Is the setup I currently have him in dangerous? Is it worth it to buy that stuff right now (as soon as it's warm enough to ship)? Or is this non-bioactive setup fine for now? What maintenance should I be doing on his tank?