I'm also in the Netherlands and received android pie pretty quickly though. I can't tell why you did not receive one. Maybe your retailer didn't sell you a device with Dutch firmware? The problem of battery draining also exists in ultra Stamina mode, in which no 3rd party app is loaded by default either.
At first I thought it was because of the removal of the "keep WiFi awake only during charging" option, which I used to enable. However the problem also persist while WiFi and 4g are disabled and also during flight mode. My standby battery usage used to be 0.1% an hour in Oreo and combined 0.9% per hour. Now it is 1% an hour in stand by and 3.5% combined in Pie with maximum Stamina mode enabled, only WiFi on and all other connectivity features disabled, no Facebook app, no WiFi scanning, email only syncing once every hour, no push services except whatsapp, low brightness, no gaming etcetera etcetera. It could only get worse with normal usage. It is not good!
