but dissuading those who want to do it for the right reasons will only skew the demographic towards those that don’t

The issue isn’t the individuals deciding to pursue a career as a cop, it’s that policing as an institution itself is broken. You don’t praise dictatorships just because you have a benevolent one right now. The problem isn’t who is in that position, it’s the position itself being vulnerable to (and inclined towards) violence and authoritarianism. If you think you can fix the institution just by filling it with the “right people” then you’ve missed the forest for the trees.