So I have seen this before and I thought to bring it up as an idea. /vote gives you keys money etc but its up to luck if you get a common, rare etc key. Most of the time you just get a vote key. In the online store add a section to buy keys in different game modes. Prison, for example, Common key x1 1.00 irl cash. Or something like that.
They have that for skyblock but I totally agree, I play survival and it’s wayyyy to hard to get a rare or legendary key.