On a side note - there are bots that don't operate on bids, they just upvote you when you send them sbd :) and usually the profit is guaranteed to be like 200% or more. Bots like these are @minnowbooster, @tipu or @randowhale.
Usually you can also invest in those bots for income :)
Thanks for that useful information! I've seen them listed at the bottom of steem bot tracker, I think. I delegated to minnowbooster a few days ago. I'm planning a future post about how to delegate SP to boost income......just starting to research that.