I found an add-on cup holder (similar to one I had for my NSX which had none from the factory) that clips behind the inner center console panel and the cup sits on (or near, depending on diameter) the floor. Unfortunately it is expensive for being a 3D printed part that needs better QC (had to sand the changeable cup part) (the NSX one was aluminum) but it works very well.

A better design would be to have a smaller diameter clip-in piece so you can size down when you have a smaller item.

a good idea anyway