Flagging is the least effective way of affecting the rewards pool allocation.
RTFM for Steem’s sake!
Upvote valuable content.

much as i hate to pimp my own posts, this is simply untrue. Downvoting is far more mathematically effective. A possible exception might be when there are other posts, paid as much as or more than the post you believe is over paid, that you believe deserve more than they currecntly have.

And even then, to get them the money you would have to take money from all posts, not just the overvalued one.

https://steemit.com/til/@sigmajin/til-the-best-strategy-for-reducing-rewards-disparity-in-defense-of-the-flag-part-i