There is no trivial way for a bot to find the most profitable posts to upvote because the curation algorithm is designed such that voting on anything is equally profitable at any given point in time. To tell the difference requires anticipating how others are going to vote which in turn requires evaluating some aspects of the post. People and perhaps some forms of AI can do this, but simple bots can not.

Self-votes are not any more profitable, there is actually no change there except: a) small payouts are penalized, which will include a lot of small self-votes in practice, and b) with cheaper downvotes it is hopefully more likely that undeserved self-votes will be downvoted (though it is not guaranteed this will happen)