Wireless communication devices, systems, and methods related to mechanisms to aid a user equipment (UE) in determining the channel access priority (CAPC) to use for a data radio bearer (DRB) on sidelink that includes multiple quality of service (QoS) flows for a transmission. The UE may receive an indication from a base station (BS) regarding what CAPC to use, or it may itself determine the CAPC based on a rule. The UE may map the plurality of QoS flows to the DRB and transmit the QoS flows using the DRB and the selected CAPC.