Working from home a few hours here or there, I didn't worry about being able to place a notebook next to my work laptop. I put it in my lap, or a nearby side-table etc.
Working from home on a regular basis for the entire day is another case entirely. The problem for me is that my notebook is wider than the space between my laptop and the edge of the desk, which makes it hard to write.
After I put the drink holder on that side, I found that it gave some support, but not enough. So I made a triangle table attachment in Fusion 360 and merged it with two laptop saver brackets and...voila!
It's not super sturdy, but my experience has that the brackets begin to detach from holding onto the desk before the side table deforms.
You need two clamps and two screws from <a https://www.prusaprinters.org/prints/26711/files>The Laptop Saver - A sub-desk level drink holder</a> and this file as well.
I printed with 1.2 mm thick walls and 20% infill.
The author remixed this model.