As you progress the overall level of competition increases, particularly on reaching Divisions.
You may encounter opponents with different might bonuses, card builds, perks/spells setups.
The system is designed to maintain balanced and dynamic battles. Because of this, you will consistently face a mix of stronger and weaker players which keeps overall win rates within a normal range.
Improving your perks and upgrading cards will increase your might and strengthen your position in future matchups.