Her ruthless mission to kill Obi-Wan made the chances of her surviving the events of the series extremely low, but Star Wars put the character on a path to redemption at the end of the series. Reva was shown leaving her lightsaber in the desert in a moment that proved she had left the dark side of the Force. Reva left her lightsaber in the sands of the desert planet at the end of the episode.
The lightsabers that were used by Obi-Wan and Anakin were the first ones to wind up there. Unless Obi-Wan Kenobi season 2 or a different Star Wars project brings back Reva and finds a way to resume her story, her weapon could have been one of three lightsabers hiding on Tatooine at a single time. The sands were home to two of these in the finale.
In the end of Star Wars: Rise of Skywalker, Rey buried the lightsaber that belonged to Anakin and the one that belonged to Leia. There are questions over how many lightsabers have been buried in the deserts of Tatooine after a reveal in the Obi-Wan Kenobi season finale. By the end of the Skywalker Saga, it was back in the desert. Reva is not the first person to take this course of action. Obi-Wan dug up the container that held them to retrieve his own, but left Anakin behind.
In the Star Wars canon, it is known that the lightsaber didn't stay in the desert.
Reva's lightsaber is one of four lightsabers that have been buried in Tatooine's deserts.
Reva was the latest Star Wars character to retire their lightsaber. What happened in Obi-Wan Kenobi shows how important this desert planet has been to the franchise.
For some reason, burying a lightsaber on Tatooine has become a symbol of a character ending or at least taking a break from their Star Wars journey. One of the weapons was buried on two separate occasions. It is not known if she ever retrieved it after the events of Obi-Wan Kenobi. Obi-Wan recovered it and gave it to Luke in A New Hope. There have been many stories in the deserts of Tatooine. Reva recanted her evil ways as an Inquisitor after giving up an opportunity to kill Darth Vader.