Some time ago, a rumor hit the internet that Obi-Wan Kenobi was originally going to feature the return of Darth Maul. Yet, as production got ready, they seemingly have removed away from that concept to feature Darth Vader as its main antagonist alongside the connections to the animated series with the live-action debut of the Grand Inquisitor. Yet, showrunner Deborah Chow revealed in an interview with Total Film that this wasn’t the case since she’s been involved with the project.
As long as I’ve been involved, we’ve never had Darth Maul in any of it. Dave [Filoni] did a beautiful job of telling that story already.Deborah Chow
There could always be a potential discussion if these ideas were very early in the concept stage of the project. Lucasfilm has probably planned on exploring this era for quite some time, and a very early draft may have included Maul before Filoni used that concept in Star Wars: Rebels. They may still have plans for the character moving forward, especially after the tease of his return in Solo, but it’s unclear how exactly they are mapping out their projects.
Lucasfilm hasn’t been very consistent with promoting their projects and we know very little about their future plans with the franchise. They are expanding with new TV series but we know very little about their theatrical release plans. We also have been seeing a strong focus on the post-Return of the Jedi era. Obi-Wan Kenobi will be the first live-action project to focus on an earlier point of the timeline with Andor following. There’s also the long-rumored High Republic series that may be completely disconnected form the rest.
Source: Total Film