T2 and CD3217 Power on Sequence
If a CD3217 does not have the LDO outputs, test the lines for shorts, otherwise the chip is missing power or bad.
Data sheet of closest Ti chip.
A bad CD3217 can often cause a loop at step 10. All of the CD3217s need to be fully functional and communicate with the SMC before the CD3217 connected to the charger will request 20V
These documents are for specific boards, but will likely apply to most T2 Mac. Any net names and designators will be specific to the board it is from.