suggestions

This has the caveat that Monthly Crescendo gets changed to provide fight speed instead of energy. If MC is not changed, I would instead suggest players are offered either only a fight speed buff (as players can purchase the other option), or a buff that provides both fight speed + one of energy/xp/kudos.

Once a player selects a buff the others are disabled and the chosen buff expires at the same time it currently does. The reason I suggest adding fight speed in addition to one of the other options is because it is universally the best "feeling" buff in the game, while not being the optimal choice if you want to gain energy/xp/kudos.

I would normally suggest just making the weekend buff fight speed as players are able to buy the other buff they need, and that is a viable option if MC isn't changed, but there is a benefit to being able to gain energy/xp/kudos without a limit during the weekend, where fight speed alone might seem less exciting.