Is drain happening on mobile data or WiFi or in general (combined) ?
My first go would be to install Gsam battery monitor, grant additional privileges via adb and see if an app is a culprit.
Does the phone overheat in general usage ?
Are you on Oreo or Pie DP ?
Other possibilities :
- low signal (especially on mobile data)
- faulty SIM card (related to above)
- try turning off (if on) WiFi and BT scanning
I think in order to get a better answer, you will have to do a bit of research and give more data on the issue. :)
You could also try if drain is present in the safe mode.
In the end, factory reset might be a good option.
Personally, I'm getting around 7,5 hours of SOT (not playing games though) , so I had to double check if I'm in the right forum :)
I suspect Location History. Is it enabled ? Could you disable it just to check.
Also, is wifi and BT scanning off ?
And , if it's already off, pls try and install Gsam battery monitor from app store, and grant adb permission to get more data from apps. Check apps in a while to see if any of the apps is a rogue one.