We are offered to play a match.

Actually, there are no weeks with higher-level monsters; there are weeks with double the population of lower-level monsters. And a +5 to the population of level 7 monsters can only happen at the end of the month, meaning it can only affect week 5. Although, overall, I agree that this additional spawn should be banned.

Just recently, I played a season game with Sir Taurus, Citadel against Fortress. On day 121, it was Hydra week! The opponent had a lot of money and seemed to have placed them in the castle, and he was able to buy 7 Hydras on week 2. With such a unit, he could easily defeat any Barbarian and any Treasure Hunter. So, it can happen.

A week with a level 6 monster is no less annoying, especially when encountered early in the secondary market, as I remember games where a week of Nags, Unicorns, and other monsters of that rank decided the outcome of an early encounter on week 2.