Just Security published on 20 April 2023 a commentary titled "The Fighting in Sudan Is an Armed Conflict: Here's What Law Applies" by Jelena Pejic, Lieber Institute at West Point.
The author describes the fighting in Sudan as a non-international armed conflict under international humanitarian law (IHL). Sudan is party to the main IHL treaties. It could be argued that the Rapid Support Forces is a dissident force under IHL.