When you want to book a one way award using United miles from the US to anywhere in the world (including just domestic), grab a second one way award in another region for some time in the future and just add a United domestic flight at the end for around 5000 miles.
I still think the elimination of award charts is awful, but there are still ways to get outsized value using United miles both because partner awards are still pricing based on (effectively hidden) charts and because United will allow you to book those at a discount based on their new lower-priced domestic awards.