Random Number Generation, or RNG, is a highly debated topic in almost every competitive video game genre.

Understanding exactly where randomness factors into the equation allows top players to mitigate its negative effects.
Initial Deck Shuffling
If your opponent rushes the bridge and all your cheap defensive counters are at the bottom of your deck, you lose the tower.

Professional players build their decks specifically to minimize the chances of a truly unplayable starting hand.
Make the best play available with what you have.Know what they are holding.It adds excitement to the viewing experience. The Unpredictable AI
While developers strive to make AI as predictable as possible, the physics engine can occasionally create chaotic results.

Leaving a slight margin for error in your defensive placements is the best way to handle AI unpredictability.
Battler CategoryLevel of LuckAuto-BattlersLuck is the primary factor in individual matchesStandard Tower RushHighly skill-dependent after the first 30 seconds Embracing the Chaos
The best competitors accept the chaos, focus on what they can control, and outplay the opponent regardless.

If you are stuck in a lower arena, it is because of your fundamental mechanics, not the random number generator.