I see that ActorCore creates a .glb file of the rigged character on my disk.

However, there is no obvious option to Export an animated .glb or glTF file in the export options (where I would expect a glb file with embedded animation(s) to be an option).

.glb or glTF 2.0 format is the most reliable animated character format for many uses such as Web3D and my game engine of choice. https://www.khronos.org/gltf/