How to use AWS IoT Fleet provisioning on FreeRTOS "release-v10.3.1", I don't want to move to AWS-FreeRTOS

Best thing to do for that is read through the links on this page: https://freertos.org/iot-fleet-provisioning/index.html - there is a bit of set up to do but there are scripts provided to automate a lot of the device registration with AWS.