It is not possible to identify one bot to be profitable as its ratio keeps on changing every time. One bot is profitable on one turn in the next turn it may end up in loss. Let’s assume a bot is giving upvote worth 1$ if it receives 2 bid of .1 $ each its vote will be distributed in the both bid in ration of .5$ each and both will end up in profitable. In the next round upvote worth is the same but if it receives bids valuing 1$ or more in next the bot will become in loss.
Considering above I will see which bot or bots are giving best profits in the round and will invest accordingly in two three or more bots.