Interesting, I use fine sand in my aquarium yet I've never observed any burrowing, maybe they don't feel the need to because I've arranged my driftwood into caves? They certainly do kick up small stem plants, so I can't recommend those, but my moneywort has been staying in place surprisingly.

I am still having light issues personally. I have a rather high output LED fixture, I've elevated it above the tank more so they're less annoyed by it, but when I turn it in, they tend to go crazy, not really sure how to get around this. Any sudden change of light seems to really set them off, even turning a lamp on in my living room can get them running for cover. I've ordered some amazon frogbit so I am hoping it comes soon to cut down the light further..