Not sure about your question regarding worms, Bordomb. Yes, worms are high-fat. But bloodworms are midge larvae with a similar nutritional profile to mosquito larvae. Both are staples in a wild Betta diet, along with the larvae of other insects..
Your tank is Betta-perfect, with that log and plenty of plants on the way to hide and take comfort in. A soil-based NPT. I'm impressed. Just needs a little topcover. Your experience credits you. More new Betta-keepers could emulate your setup.
Gorgeous fish. You really scored.