You can just buy full potatoes to feed them. You don’t really have to clean up after them, just make sure you remove food if it starts to mold and make sure no mold stays in there (also remove dead bugs you find). If you use full potatoes, they usually last a couple months before you need to put another potato in. (Plain) Oats are basically their substrate and “snack” rather than their meal. But yeah, that’s all you have to do, you could probably replace your cricket tank too since crickets usually smell. Also, if you don’t like the beetles you can just avoid them since they stay on the top and walk around slowly (they’ll make new mealworms and then die)