There shouldn't be a trade off of activity via cosmetics. It was never currency and is now currency which means the original system needs an overhaul as it created a bottleneck.

Progression and customization shouldn't be tied together in a negative pressure vacuum. If I'm active, I should get rewarded cosmetics. My activeness should not disappear as a reward, that is a punishment.

Suggest a separate currency for cosmetics. If it is tied to mana then let a percentage of mana earned be set aside specifically for cosmetics OR Lifetime mana should be shown, rank title should be unaffected and my activeness should never go down in negative integers.

Activity by definition is a net positive value, its either:
I'm active (+1)
I'm not active (+0)
I cannot go negative/down in activity (-1), I can only stop being active (+0)

With this system you can remove trade backs which just add confusion (an unneeded variable) to the equation of a person's choice at the cost of missing mana OR allow only 3 trade backs per year or once a month for free.