Can you provide an example file which *does* work?

Which Source Filmmaker version is this? Are you sure that the model isn't underground or behind a wall?

All animations are imported from a QC, but the Blender GUI makes swapping between them difficult. If you select the armature in the Source Engine Exportables panel, you will see a selector that makes switching easier.

Corrective flexes have underscores in their names. That's the only difference, at least in Source 1.

Seems like a corrupted install to me. Try deleting the addon with Blender's Preferences window and downloading it again.

All changes made to the scene are reverted after export using the standard Blender undo feature, even if there was an error during the export. Did you make the first screenshot by re-importing the exported DMX file?

In either case, please send the .blend file.

Try deleting this folder and installing again:

C:\Users\Sonic\AppData\Roaming\Blender Foundation\Blender\2.93\scripts\addons\io_scene_valvesource\

This must be done manually. UV maps and texture names are imported, you just need to locate the texture files.

The tools import and export at 1:1 scale, with one Blender unit being one Source unit.

Are the mesh and animation DMX files that you are compiling both exported from the tools? If not, where do they come from?

This object is created on import when a VTA file doesn't 100% match the imported model, to show you what the data was. You can just delete them if you are satisfied that your shape keys are working properly.