I think it all comes down to camera movement , not character movement. Character movement is constant but just based on camera direction. You want to interpolate the camera movement, which clearly does not want to move freely when the player is staying at the same location (even when rotating). But when the player starts moving the camera initiates and starts following the character. I would probably try to approach this with linear interpolation and timelines that change interpolation value of the camera movement, or a simple boolean with initiates camara movement upon a given amount of character movement… It’s an interesting problem to solve.
BTW, I would also make sure the camera is not somehow connected/attached to your player character, it should be a separate Actor.