I just did a similar update on my lumia 640. Had W10 on it, but all the apps were from 2017 and the Store failed to update them. I downgraded to W8.1 and then was able to go back to W10 via the Over the Cord (OTC) updater. Working like a charm.
I had updated to W10 on my 1020, but did it soon after W10 release, later when My wife said okay for her 1020, it would not work so hers is still 8.1. We currently have iPhone 11's and use our old WinPhones as WiFi devices or cameras.