I think I figured it out how to use this app on android oreo(if you're facing black screen or no phone wakelock or other problems) (I have blackview bv9500 pro oreo 8.1) First install older version to gain root access via magisk
After restart prepare your whitelist (i white listed Android system as well)
After install latest version of Power nap
After install notific and setup (handles notifications perfectly) everything you need
Now this part is tricky
Since power nap causes black screen we need to block this app from accessing sensors. Also we need to block sensors from phone services, call management, and other sensor using apps
Assuming you have xposed installed already
Go to play store install XPrivacyLua and XPrivacyLua pro
Activate from xposed
Restart your phone
Now open XPrivacyLua pro
Click manage hook definitions
Click cloud download
And search for power manager and download both of them
Now go back to main screen of XPrivacyLua pro and activate
Fif and privacy
Restart your phone
Open XPrivacyLua and click power nap activate the "use proximity wakelock"
Now click phone app from the list activate the use proximity wakelock as well
Now go up and search for phone and activate the use proximity wakelock for phone services and phone messaging
Restart your phone and enjoy the power nap on Android oreo!
This is my second day on testing and it perfectly works. I'm open to new suggestions as well.
Edit: i also tried with different method and its working.
Install any ambient display app from app store (i tried with always on edge app) and do the sensor and XPrivacyLua work i mentioned above and enjoy the power nap. Please confirm me if any of these methods work for you. Thanks
Edit2: I now removed android system from whitelist and testing like that. Will post results here in few days.
Edit3: it's been 24 hours and there's no problem so far
Tweaks i did : blocked sensors with XPrivacyLua from call management, phone and dialer, power nap and installed always on edge ambient display. Power nap working flawlessly now. I saved %40 more battery since yesterday. Checked with GSam battery. No blackscreen or misbehavior whatsoever.
EDIT4: i don't have any problem using power nap even blocked everything including android system. I now enabled sensor Blocker for all apps from XPrivacyLua (except always on edge) . So far no problem. This is it guys i find out how to use power nap and i can enjoy with my phone without useless idle battery drains. Tested this method over a week now.