It's the behavior for all apps and I don't think it can be customized. There are...

burnedtoast on Jan 13, 2024 | parent | context | favorite | on: Blur Radius Comparison

It's the behavior for all apps and I don't think it can be customized. There are some APIs to affect the spot shadow color and ambient shadow color (from API 28), but no way to affect this offset / light source position AFAIK.