If the Sun is 5005 km up and 45 km in diameter, and if it was spot light, it would still

make shadows of smaller object be smaller than the object and have umbra and penumbra.

In both models, Flat or Globe, Sun's angular diameter is 0.5 degrees.

If that smaller object is 5 meters in diameter, and at altitude of 1000 meters,

it would have angular diameter of 0.3 degrees. It is not big enough to cover Sun's 0.5 degrees.

Edges of the sun around the object will shine inside the projection of the object, converting edges of the shadow into penumbra.

Whether Flat or Globe, we would still have situation shown here:

https://www.theflatearthsociety.org/forum/index.php?topic=74067.msg2016194#msg2016194with one "little" diference: there's no point at the ground where the whole Sun is covered, so shadow won't have umbra at all.

It would have antumbra, as described here:

https://en.wikipedia.org/wiki/Umbra,_penumbra_and_antumbra.

To make umbra, the object has to be closer to the ground.

Shadow smaller than the object means what?