Greetings Big Sur users!
I've written a post before about this topic and the problem isn't resolved as I expected. Following the methods I've found on the official community page of apple and from 3rd party suggestions I came to the conclusion that it's way deeper in optimization of the OS.
I've reset the SMC, PRAM/NVRAM and run Diagnostics (at the request of Apple Support) - no issues to report except that now I can't access recovery mode which would be necessary to reinstall the OS. I almost always see the 'Using significant energy' alert when I'm using Safari - which is always, however at most, I've got only a few tabs open (not more than 3). I'm not running any other applications, since.
Many suggest to disable the ¨Spotlight app.¨ for most categories (this got me less energy use in general from the battery).
Some others who are using Chrome or any Chromium based browser faced issues with ¨Chrome Helper¨ constantly running in the background without the Battery Monitor showing its significant drain - stopping this process (from the Activity Monitor) gave most users a better image of their battery time. (I use Safari so that's not the case for me)
In conclusion of trying every method suggested, I would like some response from the Users and Apple himself about this topic.
Thank you for your attention!