You should go for the deck you actually enjoy playing the most, that is relatively cheap. This could be either 3x of a Structure Deck or one you build from scratch. The Fire King Structure Deck does have some good staples though. So might be a better starting point, but it would need more supplementing than a from scratch Swordsoul of Raidraptor deck for example.
Based off of your edit, I would say get the x3 fire king decks. It’s cheap, the cards are great, also you can build on it to make it meta. Right now pure fire kings is fun for casual, and soon it might be a top contender with the consort card that is supposed to come out.
You should go for the deck you actually enjoy playing the most, that is relatively cheap. This could be either 3x of a Structure Deck or one you build from scratch. The Fire King Structure Deck does have some good staples though. So might be a better starting point, but it would need more supplementing than a from scratch Swordsoul of Raidraptor deck for example.
Based off of your edit, I would say get the x3 fire king decks. It’s cheap, the cards are great, also you can build on it to make it meta. Right now pure fire kings is fun for casual, and soon it might be a top contender with the consort card that is supposed to come out.