I think the solution is to only allow people to upvote any account 2x a day including their own. There may be a way to circumvent this but it would have to be very elaborate to work.

This would prevent some of the high frequency posters from getting a disproportionate share of the reward pool. You can't put out "quality" 4+ times a day. Even if they are well written they will lack quality of thought and ideas.

This also means a more even spread of rewards. Whales would be forced to find more quality posters instead of relying on 2 or 3 high frequency posters.