Hey @Poo_Blues17 and welcome to the Ubisoft Discussions!
I understand that the graphics settings for Rainbow Six: Siege reset every time you launch the game. After looking into this, this issue might be caused by the fact that the "GameSettings.ini" file is set to read-only. This would mean that any changes made in the game cannot be applied to your Settings file. The game's settings file is located in - Documents\My Games\[Ubisoft ID].