First off I want to say that I know little about power. My goal is to print a case for 4 of my Rock 5Bs and supply power from an internal power supply.
Can someone point me in the direction I should go. Ideally I want adequate power as if it were running at full utilization.
There are entire threads here about powering Rock 5.
Formally speaking it should be powered by a USB-PD brick.
In practice some users have plugged DC barrel jack adapters to USB-C, giving the board fixed 12V on power pins, and the board runs fine without proper USB-PD negotiation, mostly because it’s MP8759 chip powering everything downstream with 5V and up to 8A of power. That’s 40W at full utilization but you’d be hard pressed to get there - like a utilisation of NVMe drive and all USB ports at their full at the same time. Power consumption barely reaches 12W during a stress-test: