I really get screwed by the fact that stage ends early if you complete the goal, leaving my upgraded upgrades unused. Its double rng and a good deck can get dumped at stage 6 while an unsustainably bad deck will linger to stage 9 with no hope to get past because it was investing in consistency rather than growth. You can cheese it with extra rounds but the lack of investing into upgrades will catch up quickly, and the extra rounds are the third rng.
This is officially gambling³