Did you verify that either fill or stroke of the new objects is set to a visible color with opacity > 0 and transparency A (alpha) > 0?
Draw a new object, and while it is still selected (bounding box handles visible) open menu 'Object > Fill and Stroke…' and inspect the RGBA and opacity values for 'Fill > Flat color' and 'Stroke paint > Flat color'.
Did you verify that either fill or stroke of the new objects is set to a visible color with opacity > 0 and transparency A (alpha) > 0?
Draw a new object, and while it is still selected (bounding box handles visible) open menu 'Object > Fill and Stroke…' and inspect the RGBA and opacity values for 'Fill > Flat color' and 'Stroke paint > Flat color'.