[Xperia Z5 Compact General] --jenana--:
I'm only testing for one day, so this is not gonna be complete.

My experience.

1st attempt

to install Nougat, I did a clean install (the same as you), restored data partition I had, rebooted and flashed gapps. After that I debloated (uninstalled) some apps and I heavily restricted MyAndroidTools.

It was a mistake.

A. Dirty flash (or restoring data partition from MM) caused the same heating and battery problems.

B. A lot of apps wouldn't work properly (crashes), probably a combination of dirty flash and too much debloating.

C. Some apps wouldn't work, like WhatApp couldn't connect to the servers anymore. Maybe because of the dirty install, maybe because I blocked some stuff from Google Play Services in MyAndroidTools.

(I didn't take much time to investigate what was going wrong. I just moved on.)

2nd attempt

Complete new clean install, also with 32.3.A.0.378 and patched/rooted stock kernel.

Flashed Gapps (before first boot) with aroma installer. I immediately removed what that aroma offered me to remove.

Google Play Store automatically reinstalled my apps. I didn't install MyAndroidTools anymore.

Optimalizations:

** Settings **

Location mode is still on high security (don't know why, probably I forgot about it)

Location > (3dots) Scanning > WiFi-scanning off / Bluetoot scanning off

WiFi > (3dots) Modify network > Static IP and DNS (not DHCP)

About phone > Status > Charging optimization OFF

Data Usage > Data saver ON > added a few exceptions to my list

Battery > (3dots) Battery Optimization > I added messengers/chat, Greenify, Alarm Clock (Xtreme), Tasker, Transparent Weather Widget

** Some debloating **

I uninstalled a few apps like OfficeSuite, AVG Antivirus, Playstation and crap that could be easily uninstalled.

In Titanium I frooze a whole bunch of apps. For reference, this is a zip with 9 screenshots of apps I frooze. It's work in progress, that list might become bigger or smaller. It's stuff I don't use, I knew(/hoped) it could be froozen safely or I replaced it with a 3rd party app.

** Extra's **

1 tasker profile to switch off auto-sync at night

Kernel Adiuator to change

CPU governor: BIG to powersafe // LITTLE to interactive

GPU governor: powersafe (Probably not the best option)

I/O scheduler: noop​

Doze Settings Editor with the built-in "GeraldRudi"-profile.

Greenify with Shallow Hibernation ENabled and Aggressive Doze DISabled (I might try if it's better to put it on, somewhere in the future when I feel like)

** Result **

No performance issues (yet). No crashes at all.

No issues with sound or volume whatsoever.

Probably the thing where I powersaved GPU is too much. It causes stuttering video and makes it a ***** to play games on the phone.

Phone doesn't get hot anymore.

Excellent battery life. During my first test I already tested behavior while idle/screen off. During 10 hours, battery drain was 0,0% per hour. (This is my Better Battery Stats log)

For reference, I did a Antutu Benchmark, but I don't know (yet) what I can learn from these numbers.

Optimized for battery life: 32853 is a BAD benchmark. (3D: 16625/ UX: 7862/ CPU: 6354/ RAM 2012).

I did one benchmark with the standard CPU and GPU governor: 75444 (3D: 38623 / UX: 17323/ CPU: 13454 / RAM: 6044)​

** Conclusion **

A. There's nothing wrong with 32.3.A.0.378, but I definitely recommend a FULL wipe before you install it. In fact it doesn't matter too much which Android you flash, or which kernel. Impact of that version is neglectable. In other words: if you experience problems with functionality, battery drain or overheating, a dirty flash with another (or a newer) android version is NOT gonna help you.

B. Android 7.0 + Z5C can give you an excellent battery life without overheating.

C. Finding the best balance between powersaving and performance needs more testing. This can be different for every other user.