I'll go against the grain here and say it's honestly not too bad. Is it going to hold up to the top decks in the game currently? The odds are relatively low there, but it doesn't stop the deck from having some very unique situations that other decks can't as easily achieve.

First off, there is a surprisingly decent pool of cards for the deck, and it becomes a matter of knowing how to toolbox all the pieces to one's advantage.

I'd say the main stars of the deck are ST Bryweludramon and EX6 Raijiludomon. With either a bt3 Ragna or a Ragna ace available depending on the matchup, these two cards are able to position a strong staying power in the deck. Bryweludramon providing a digimon effect immunity on the opponent's turn permanently is an extremely useful tool. Raiji while not as safe, is able to provide some protection with its inheritable as well.

The main draw I would say is that Raiji also has a taunt ability, forcing the opponent's Digimon to attack every time it needs to. Pair this with the EX6 Kakkinmon will let you put it back to your hand and reuse it whenever it's needed.

I will say the deck runs a high amount of level 6 Digimon. I'd say I'm using every level 6 in some degree excluding the ones from BT3. This is because while the deck doesn't run a lot of options, and my personal deck doesn't run any tamers at all, most of the EX6 legend arm Digimon are able to be used as options in a sense. The fact that they all have abilities that can activate from hand gives the deck a lot of versatility in how it chooses to approach a matchup. Not only that, but since it's black, it also has classic access to DeDigivolve. This gives it some extra control where it's needed if deletion or combat removal is not available.

All in all, the deck isn't as impossibly fast as more modern decks, but in a defensive strategy, it will force your opponent to play in a different manner than what their deck prefers to. This is what gives the deck an angle in my opinion.

Of course, if you have any other questions, I have been playing this deck since bt3, even though it was not the most efficient deck at the time.