Why don't I see Twitter's homescreen widget on my Android?
Sorry, the Twitter widget is gone.

The Twitter widget was removed from service in the newer versions since release 6.8.0. See the report dated July 26, 2015 from Android Police. It is possible the version you are maintaining on the earlier OS was never updated (or can't be) to a widget-less version.

My Samsung S8 carries the latest Twitter App and no widget available, regardless of launcher. (I use Nova, but confirmed this too, by reverting to the default)