While <em>Rise of Skywalker</em> did have "Evil Rey" wielding a doubled-bladed red lightsaber with a hinge feature, doubled-bladed sabers aren't exclusive to dark side s. Likewise, original scripts and concept art for Colin Trevorrow's Episode IX did see Rey with a double-bladed blue saber. I think this would have been extremely cool, and would have made perfect sense considering her prior still with her Jakku staff.
