The Z390 Phantom Gaming 7 shows us the goods with the heat sinks removed!
It looks like ASRock has embraced the DrMOS trend of these mid to high-end Z390 motherboards. The CPU VCore is eight phases doubled by four ISL6617 doublers, the iGPU is two phases, and the VCCIO and VCCSA are single phases. The PWM controller is a digital PWM from Intersil, the ISL69138 in a 4+2 phase configuration. The power stages are Vishay DrMOS SiC632A for the iGPU phases and DrMOS SiC634 for the CPU VCore, and both are rated 50A.
The VCCSA and VCCIO are controlled by APW8720 integrated PWM/driver chips and control smaller MOSFETs from ON Semiconductor. The memory VRM is two phases using the same PWM and double the number of power stage components as the VCCIO or VCCSA phases.