The Billy the Kid series is actually pretty good, in my opinion.
These days the more well known are ones they combine the genre, so you end up with a modern day version of a Western like Justified or a Sci-Fi'ish Westerns like Outer Range which was also good, but was inevitably canceled. Of course, the Westworld HBO series is good, and the same people involved in that worked on Fallout, which is again like a Sci-Fi Western. The Mandalorian is defined as a Space Western. I like the sub-genres, but sometimes I want pure classic Westerns. Stuff like the first couple seasons of Hell on Wheels, but still decent enough to watch until the end.
The problem with Western series is that they're either good, but fail and get canceled or start amazing and continue until they're stale and boring, like most shows. It's usually just better to hope for a good movie instead.