Battery issue (+WiFi drops) since updating to e/OS v3.2

Hello and apologies if this is in the incorrect topic thread. The issue pertains to the following device:
Murena One
Previously running 3.14; upgraded to 3.2 (currently running).

Apps are minimal (email, firefox, DAVx5) and no change have been made to fetch etc within the past (min) 3 months. Nothin has been added, taken away or changed- the phone has merely been used.

The issue started when the ADVANCE PRIVACY component lost its mind in notifications - I have seen the other thread. None of the fixes worked, and 3.2 had just been made available so I upgraded to e/OS 3.2; at this stage no noticeable battery drain was apparent.

The 3.2 upgrade took forever, with the download pausing regularly. No WiFi drop had been noticed at this point and eventually it updated.

SINCE v3.2 of the OS has been installed, battery drain was awful - massive in fact. Battery manager showed nothing. WiFi also kept dropping, visibly it would disconnect and either reconnect OR stay off for some time. Battery manager showed nothing and I experience 0 other issues with WiFi devices across the house.

Switching to Aeroplane mode (with Wifi, mobile…everything else…switched off first yielded no results. The batter drains irrespective of wifi, network, aeroplane, bluetooth, NFC (etc) settings being on or off.

At this point a full factory reset was in need, to eradicate any issues.

This has not worked. A full reset still shows the battery draining ~14% in 2 hours but only 4 applications listed, each consuming 1% or 2% - this leads me to suspect the OS is the drain. This ~14% fall occurs with 2 hours of doing nothing and with no apps installed above the base apps that are preloaded. WiFi is on (and no longer dropping) and there is no longer a SIM installed in the handset - mobile services are all off (as is bluetooth, NFC etc); battery however continues to plummet. I have switched on battery saver - no change. I have manually shut Advanced Privacy - only because it keeps restarting itself and showing as on - also no change. Screen brightness is very low, however once more - the battery falls rapidly without being used at all.

I wanted to know - has anyone else experienced this? Is there a known bug in 3.2? Is there anything that can be done that I have missed?

Apologies for the above being quite detailed, but I wanted to ensure that my steps and logic are out there, hopefully to be picked apart and resolved. I see that e/OS v3.3 is scheduled perhaps for November, so I am hoping that there is an inherent issue within the OS and the update will restore the phone to use; presently it is unusable as a daily driver, such is the battery degradation.*
*
*at no point does the phone feel warm/hot - the phone is not working particularly hard at all.

this one neither? Advanced Privacy Notifications - #2 by tcecyk

The batter drains irrespective of wifi, network, aeroplane, bluetooth, NFC (etc) settings being on or off.

severe. There’s a few on-device and off-device tools to look into it. I’m a fan of battery-historian (example threads, mostly fairphones), but it’s developer tooling.

I saw some mentions of “increased drain” at the 3.2 feedback thread, but not specifically for the Murena One - but as you said, it started with 3.1. Discourse can do in-topic search per thread, you might want to go through them

thanks for the above - that is really useful. I have further updates but they appear to be related to e/OS 3.2 and so looking to repost this thread in the OS-related topic will probably work best. In short - flight mode is fine, but when operating outside of aeroplane mode, WiFi drops are so frequent that I suspect it is draining the battery in doing much more work than before in searching, connecting, re-connecting etc…