Transfer function of a Voltage-Fed PCM-controlled Push-Pull converter in CCM and DCM modes

I am designing a Voltage-Fed Push-Pull converter, and I would like to determine the system's transfer function in both CCM and DCM modes. The control will be in Peak Current Mode. I am reading through Christophe Basso's seminars, which are absolutely fascinating, but unfortunately, I don’t fully understand them. How could I model the PCM-controlled push-pull converter using PWM switch model in both CCM and DCM modes? Should I derive it somehow from the buck converter?

EDIT:

Here is the schematic:

Answer for Andy aka:

Very simple. My minimum output current is 10mA (The maximum is 1.25A). If I want to operate in CCM, a very large Lx would be needed in the circuit. The P0 output power will be 500W (at 400VDC output). I plan for the converter to operate in DCM mode below 50W, which is why the transfer function for both CCM and DCM modes is necessary.