MacOS Big Sur MacBookPro 2020 disable energy drains
Disable settings that prevent the Mac from sleeping or let it wake up overnight in your backpack and drain half of battery.
On top of those, it's probably best to not leave any USB thing plugged to the Mac before putting it to sleep (including YubiKeys).
Enable hibernation (i.e. write to disk)
sudo pmset -a hibernatemode 25
Prevent bluetooth from waking the device
If you don't want your headphones or keyboard accidentally wake your Mac:
System preferences > Bluetooth > Advanced > untick the last checkbox Allow bluetooth devices to wake this computer
Disable "power nap" and "wake for network access"
System preferences > Battery > Battery in left menu
System preferences > Battery > Power Adapter in left menu
Other things to check
In Activity Monitor you can check the most energy-draining apps, and whether they prevent sleep.
For example, when you play a YouTube video in a web browser, it prevents sleep.
