If this system fails, the game becomes a frustrating, unplayable mess that bleeds players instantly.

While this conspiracy theory is widespread, the reality is much more mundane and focused entirely on mathematical fairness.
Trophy and Rating Systems
Most modern strategy games utilize a modified version of the Elo rating system, originally designed for professional chess.

If the system matches you perfectly, you should mathematically have a 50% chance of winning every single game you play.
Understand that a 50% win rate is normal.Because there are fewer Grandmasters, the algorithm struggles to find perfect matches.If you drop trophies, the algorithm matches you against easier opponents. The Free-to-Play Dilemma
The standard Elo system works perfectly for chess because all pieces are equal, but tower rush games feature upgradeable cards.

The system will try its best to match you with someone who has the same trophies AND a similar tower level.
Algorithm CheckImportance LevelCurrent RankAbsolute Highest PriorityAccount StrengthThe system tries to match levels, but will abandon this check if the queue takes longer than 10 seconds True Fairness
By artificially capping all card levels to a specific number, the algorithm can rely purely on the Elo rating.

Trust the math, ignore the conspiracy theories, and focus on improving your own gameplay.