Just wanted to share (and hopefully this shows up in Google because I was looking for this topic for a while until I decided to finally make a video) - upgrading the Sonnet eGFX Breakaway Box power supply works.
Went from 350watts + RX 580 to an Enermax 550 watt (sfx) PSU + Vega 56.
Went from 350watts + RX 580 to an Enermax 550 watt (sfx) PSU + Vega 56.