Of course, writers could always throw in a line on how they’ve worked together before, perhaps through Amunet’s operation she ran in Central City.
The only real hangup with Amunet Black getting associated with the Rogues would be her lack of an introduction.
Leslie JoCoy walked free following her time on the series, so The Flash would either have to show her captured or find some way to establish a connection between her and members like Weather Wizard and Trickster.