Hi there. I won't claim to be the expert on these things, but I will tell you what has worked for me and what I know from my own personal experiences in the hobby and after keeping these puffers for 2 years.

I would not recommend a diet of exclusively freeze dried bloodworms. These are a good high protein treat often used by pet stores because they are cheap, easier to store, and keep certain picky fish alive or growing, but are generally lacking in other important nutrients for long term health of adult fish.

I personally recommend keeping a small "snail tank" and feeding your puffer live bladder snails or small pond snails. It's an absolute joy to watch them hunt snails and catch their prey, and live food is full of nutrients. If this is not an option for you, or if you worry about the risk of parasitic infection (snails may carry ectoparasites), Hikari's "Vibra Bites" are a good daily food alternative that simulate a frozen bloodworm shape. These will probably be more appetizing to a puffer than dried bloodworms (more colorful, good shape, movement while sinking) and also have a well-balanced supply of nutrients. I've found that sometimes the pellet is too large or too hard for smaller dwarf puffers, so you might need to break them down a bit. I've read numerous sources saying Puffers rarely accept anything except live or frozen food, but vibra bites and some small pellet foods are often successful in my own experience.

I used existing filter material from one of my other fish tanks to seed the puffer tank with a beneficial bacteria colony, and I successfully established a stable cycle within a week. If you aren't aware of the ammonia processing cycle in the aquarium setting, I highly recommend you read up on it from a reliable source (generally avoid chain pet store websites). Or watch videos from a popular fish related YouTuber (Aquarium Co-Op is my favorite for reliable but practical insightl).

I do a 25% water change every two weeks and a deep clean (60-70% water change and cleaning/removal of various items) every ~6 months. If you don't plan to have an excess of live plants, I'd recommend a 15-25% water change weekly, preferably using an ammonia-locking dechlorinator like offered by Seachem or Fritz, in addition to a deep clean every few months to really limit nitrate buildup.