I just want to bring up a few points about parasites.

The eggs are microscopic, so you will not see them. It is not unusual for a heavily infested animal to only shed eggs invisible to the naked eye and no worms. So if the lab found roundworm eggs, trust them when they say that they are there even though you have not seen them.

Different species of parasites have different incubation periods. If there is a chance for an egg to fall off the poop into the substrate, where it is left alone for four weeks, it could hatch and your animals could reinfect themselves. Or some species have a tough oocyst that waits until it is ingested, then "hatches" inside the gut. I am not saying that changing every four weeks is not enough to prevent ammonia buildup (I have no expertise in that), but it is definitely not enough to say that by itself, it is preventing parasite transmission or reinfection. When dealing with parasites, cleaning has to be at least daily.

I'm not sure if there are frog parasites that can be transmitted to them via the insects they eat, but it is very likely that there are some out there. Many parasites spend each life cycle in a different species, so I would be very cautious of feeding wild-caught insects.