Problem solved
While it does scale down in the late game, a three-mana draw-three in the early to mid-game is great, and giving your opponents cards with it might not even be bad, especially if you run effects that profit off of exactly this
Banner of Kinship Banner of Kinship can provide Coat of Arms levels of board pump, sometimes enough to end the game on the spot, but it also has the failcase of being a complete blank if you have no creatures in play already
Instead, I just tried out a standard match against another human player
On the other hand, Lorcana can be played with more than two players, which is where Sisu pops off
My verdict: The Sapphire & Steel Deck is best for duelists who prefer a defense-heavy, resource-driven playstyle that wins through stability and strength