Where?There´s something else called doze at play, which puts the phone to a "deeper" deepsleep state if no motion etc is detected for some time (e.g. overnight). If you constantly check the phone, this mode is likely never be entered.
I found only Background app management accessible from battery settings (general switch) or it can e accesed from any app-info-battery. I couldn't find there doze at play.
And there is Adaptive battery settin which you didn't mention. What this option does?
And there are also some battety/ram related option - OptiFlex. Could you please advise how is it working? Does it also send apps in background to deep sleep which are not ticked in OptiFlex or it works different way?
And .72 update OTA is released. Are there any kernel-related changes?