port ubuntu kernel to rhel

I need to port ubuntu kernel with HWE to RHEL 9. I have experience in fedora like systems but not in debian like systems. I have Downloaded the kernel source using apt source but don't know what to do next because there is single big diff file for patches so I am not able to cherry pick things. My goal is to: 1. take ubuntu kernel source 2. Add rhel specific customisations 3. package in rpm