LoneWolfWagen made an amazing design for a desk underneath an Ikea Svärta loft bed.
As that is currently the bed I am still using I benefited from it greatly!
However, I used a desk that is a little wider and has my PC monitors on it. So I needed the table mounted a little off-set from the support beams and with a little more structural support.
This is a bracket that allows that.
Heads up: The side of the desk that I have sticking out on the open side is supported by a Kallax 2x1. File for that incoming soon. It's recommended to do something similar or grab a set of table legs for that side if you lean on it with a lot of force.

The file is slightly modified (Trimmed away the mounting plates as they were not needed in my setup) but does retain the original mounting holes. The 4 new screw holes in the arch are designed to take 4x20 metric panheads screws, as the inside cup is 4mm from the surface, meaning a 20mm screw will penetrate 16mm of wood - most tables are 20mm or more thick. This takes advantage of that and firmly grips it.

Personal tip for structural parts: Wall count. This used a Wall Count of 5 for top layer, bottom layer and general walls. Wall Count is strength! I coupled it with honeycomb/hexagon fill at 15%. You could potentially drop it lower because of the wall count but it's better to err on the side of caution.