Did you all try what Maksym Sydorov (and Nokia support) suggest?
Settings > Apps & notifications > App info:
Tap the menu (3 dots top/right) and select Show system.
Scroll and tap Battery protection, tap Storage, tap Clear Cache.
Please also make sure everything is updated in the Store:
Open Play Store, Menu top/left, tap My apps & games.
Yes, I have the same problem. After updating to Android Oreo battery is draining much faster as compared to Android nougat. Battery backup has reduced a lot.