can't find any info on this topic on the internet.
does it use the a/b partition scheme (seamless updates) such as pixel phones? because sometimes, an update uses an enormous amount of time on step 1 of 2. so maybe one possibility is the a/b partition?
Now I can see it myself with my new Nokia 8 ;-)
It installs updates in background after downloading - very cool feature, which usually only Google Pixel devices have!