Sort of solved for me..
I did install the gsam battery monitor and without rooting the phone I did the whole installing of drivers on pc and gave the app special permissions so I can see the advanced info on my phone.
The stock messaging ( sms ) app was a major culprit.
Kept cpu awake and used around 30% of all power used on the phone ( without ever openeing the messaging app. ) And keeping cpu awake uses even more power, so I guess its actually more than the 30% it uses.
So I uninstalled it and use a third party sms app now - and I got I would guestimate about 85% of prior to Android 8.0 battery life again.
Phone no longer runs hot.
