While it is true that SHORT TREKS had no time travel episodes, I'm on the fence on whether it can be called a series or not.
Part of the reason why I don't consider it a series is because of how short the episodes are. And part of the reason why I do consider it a series is because it does expand on STAR TREK a bit, which is by definition what every show has done since TAS.
It's a strange paradox, honestly.
It’s a glorified webisode series.