I don't have enough space for a proper end table, so this is the 3rd version of a table that I made for my armchair. It's parametric and can be modified for different arm diameters and table sizes. Mine is 4.75" / 120.65mm diameter and has an angle of 5 degrees from horizontal. This should fit similarly shaped armchairs or sofas with a bit of parameter modifications. For a sofa, consider changing the TopY parameter so that it's longer than the default.

I like printing with fuzzy skin on top so that any objects on the top of the table are less likely to slide off. I also print using one of the flat sides (usually the largest one) on the printer bed.

I recommend PETG or a higher temp material since PLA has a tendency to deform when using with hot coffee mugs.

The parameters can be modified in Autodesk Fusion to custom fit this for your needs.