There ought to be Recovery mode in Android 8.0 Oreo. Settings -> System -> Reset -> Factory Settings. I have Finnish Android, so some of the terms may differ slightly.
They figured out how to reliably access the recovery menu by using the phone buttons over at xda-developers.com ...
It is vital if/when the phone is stuck during boot or in a boot loop.
I can confirm the procedure works on my Nokia 6 TA-1021:
Android version: 8.0.0 (Oreo, stable)
Android security patch level: February 1, 2018
Build number: 00WW_5_22A
Power off your phone.
Connect your phone to a charger.
"POWERED BY android" logo will appear, followed by the battery charging screen.
Hold VOLUME UP + POWER BUTTON for 10 seconds, release.
During the 10 seconds, your phone will power cycle, followed by the "POWERED BY android" logo, followed by an image of Bugdroid (Android robot) with the text "no command".
If you see the the NOKIA logo instead of Bugdroid, you released VOLUME UP + POWER BUTTON too early or too late. Start over.
From the "no command" screen, hold POWER BUTTON, tap VOLUME UP, release POWER BUTTON. This should take you into Recovery Mode.