Finding myself quite pleased with battery life on my Teracube 2e emerald (1.8.1-r-dev). It was already better than any of the other devices but this last cycle was great.
Haven’t been using the phones much so usage was really light. Networking always on, WiFi mostly. Data only SIM otherwise.
More surprising given that I don’t do battery management and battery optimizations are disabled throughout most of the system.
Something I tried out last year based on recommendations from the README of this Magisk module…
audio-misc-settings/README.md - GitHub
[ originally was looking at the module to see if it was ideal for dealing with call audio quality of VoIP. I no longer have a cell number for the device ]
The recommended battery management disabling paragraph was copied, pasted, cleaned, sorted, and put into a note for future ref. Applied on other devices, too.
Seems to me, not optimizing battery hasn’t hurt anything.
Battery info shows I still could’ve waited until the next day before charging but I was getting antsy. Hurry up and drain already! 
With this kind of drain I bet it would last forever in airplane mode.
Mentioned in a previous thread: The device has no usage stats. Been that way since the first emerald build. Hence the use of a third party app. Have yet to check if there’s a Git issue for that.