I don't really believe that Dis and Shadows are stronger I just think they bring fairly straightforward tools that don't really require a high level of play to implement.
Shadows is just essentially easier to play effectively. They are probably one of the strongest sealed houses to get but for Archon format you can and should look at your opponent's decklist to know what tools they have on hand. There are quite a few cards in Logos specifically that can check a Shadows player aember stealing and if you can ignore elusive their creatures die in droves to low damage removal.
Dis is generally strong control or removal so overplaying against them is just going to get you board wiped or locked down.
Keep playing games and getting a feel for the pacing of the game. It is really cool how almost every one of my games has felt very different even in best out of three matches.