Have you tried a factory reset? I know it's a pain but if you plan it out right, it's not that bad to restore your apps and such. This is assuming it's not some rouge app draining your battery after an update (e.g. Facebook Messenger, etc).
Honestly I've never found that things like Greenify and such really helped battery life materially. The right custom ROM can significantly change your battery life, but takes a bit of trial and error.