When Nokia 8.1 got the Android 10 update, some users reported it came with the October security patch. Fort the majority of 8.1 owners, the October security update wasn’t available till recently. The update should show up on your device now, but it is just 3.2 MB large.
If you are next to your trusty Nokia 8.1, do check if the update is available.
Thx Michal for the tip and screenshot. Dark mode does look cool!