Before you read The Sisters of the Red Room.

Based after the events of Black Widow (Spoilers ahead), this shows where and what Yelena Belova does afterwards along with the other black widow's. Yelena alongside Y/N and other's go and free the other red room black widow's across the world using the anti mind control serum (As Yelena calls it) who are still induced with mind control.
This has action, a bit of romance and you get to see more of Yelena Belova. This is my take on what happens after and may not be accurate and Yelena is portrayed with her personality to the fullest.