First off, unfortunately based on the size compared to the male, that individual looks like a nymph, and at the slow rate these things grow, might still be a few months until it matures, (at which point the male will be dead). Medium/large Arenivaga nymphs are fairly easy to sex from above, males develop larger, more curved thoracic segments than the females do, as they're going to have wings eventually:
In some species this is more obvious than others, and it only works on medium to large nymphs, younger ones look much the same as each other.
Alternatively you can sex them from below by looking at the last ventral segments, females have one big one, males have two smaller ones, here's a pair of A.bolliana nymphs:
Secondly, you'll want them on several inches of coconut fiber, with only an inch or so of leaf litter on top at the most, they have small appetites and don't eat all that much, and appreciate a decent amount of fine substrate to burrow into, sounds like you've got yours set up the opposite of that with a very thin layer of actual substrate and a whole bunch of leaves... 😅 Small containers are actually preferable for this genus though.
Thirdly, I don't know if these are A.erratica or not, there are many, many similar looking species, and with the exception of very distinctive, unmistakable ones, (which these are not), the proper practice is to label them Arenivaga sp. "insert locality here", until we can get a taxonomist who specializes in this genus to take a look at them and give us an ID. The locality information is pretty important when getting an ID, usually we use city or at least county names.
Hope this helps! In short, I'd go out looking for more females/nymphs if I were you, even if yours is a female nymph you're gonna need male nymphs to get her mated. Try checking animal burrows, they really love hiding in those.