[Official] Supermicro X11SCV-Q LGA1151 Mini-ITX - Quick build

I am having a reboot issue with this motherboard.
Has to do with the PSU, but why/how eludes me.

With the FSP250 that came with the Chenbro chassis:
Reboots suddenly when accessing NVMe (same time or shortly after starting read/write)
Seems to be stable when booted from USB or SATA

With an old Dell NPS-250 PSU I had lying around:
No reboots (yet)

With a brand new EVGA 750
Reboots suddenly & randomly, doesn’t finish boot of anything

Before swapping PSUs, I previously swapped out every single other component: NVMe, mobo, CPU, RAM.
The only thing that stopped the reboots was my old salvage power supply, which I don’t want to use because the fan is noisy and annoying.

Any suggestions would be greatly appreciated.