Unfortunately, there is no knock-out system for seasonal engrams. This means that you can always get duplicates of things you already own (apart from ghost projections, ornaments and emotes that you unlock). This is happening here. You are getting duplicates and not the things you want. This is subject to RNG and Bungie can't (and won't) do much about it. Sorry to hear that you didn't have a good experience with the engrams.