I think the stupid ending is more due to how the story was handled than anything. In the light novels, Endless Eight is just a one chapter story, at maybe a 20 minute read, so the ending was perfectly satisfactory to me in that context. Now when they somehow manage to drag it out over 2 months worth of copy/paste TV episodes, then it's incredibly underwhelming.
If they stick to the novels without doing anything crazy, the rest of the season should be enjoyable though.