⚠️ The 1U mount is strong enough to hold the PSU, but it does wobble.
For the 1U I recommend using the 10" panel version and remixing to fit anything you may need next to the PSU.

FlexATX PSU rack mount for 1U (horizontal) or 2U (vertical)

I made this for 10" mini-rack projects where you need an external PSU. Such as for SATA power, extra fans or PCIe risers.

Though they will work fine in a 19" rack as well. (And look comically small!)

FreeCAD model included for remixing. Please share if you do :D

Edit: included .step files as well as exporting from FreeCAD may be unintuitive if you're not familiar.
But if you find the .step files are somehow broken, see if the FreeCAD file works for you instead.