I don’t think it has to do with the battery saver. Mine didn’t work either yesterday and this morning, all of a sudden after updating apps through the playstore, the assistant started working again (the only Google related app that got updated was Android System WebView).
another interesting thing was, it was the same on my old Samsung Tablet and that got to work again at the same time.
still have some issues with the assistant app like it doesn’t launch from the drawer, nor from a shortcut, different build numbers in the app info compared to the info that’s given in the Playstore, stuff like that.

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