It looks like the Hercules RM48L is supported by freeRTOS, but not the RM46L.
These both use the Arm Cortex-R4F CPU.
Will freeRTOS run on the Hercules RM46L series of MCUs?
Use the search box on the top left of the forum for R4/R5 related posts. You will find that the discussions say that provided the cores are the same, FreeRTOS will run on all RM4x RM5x parts.