If you "Fill Uncut Surfaces with: Own Surface colours (Shaded)", you will find you don't have the shadow fill and colour option.
Choose "Non-Shaded" and you can control the shadows.
Barry.
One of the forum moderators.
Versions 6.5 to 27
i7-10700 @ 2.9Ghz, 32GB ram, GeForce RTX 2060 (6GB), Windows 10
Lenovo Thinkpad - i7-1270P 2.20 GHz, 32GB RAM, Nvidia T550, Windows 11