To slightly answer my own, most recent question and to complete my second initial question about adding keyframes to an animation track for the Gradient in a Gradient Layer of the Shader:

As shown in the picture below, if you right-click on the “Layer” parameter of the Shader, navigate over User Interface, and click ‘Show Subchannels,” you can then see all the parameters of the Shader Layers. You can then drag the Transform Angle parameter into the console and get its description ID. Doing this, I was able to get that the dynamic DescID of the Transform Angle parameter (like you showed before): “Layer[c4d.SLA_LAYER_BLEND, 10120].”
dev response1.PNG
Putting this into the correct DescID format, I can create an animation track for any of the Layer parameters. I can create an animation track for this specific Transform Angle parameter with the above DescID.

c4d.DescID(c4d.DescLevel(c4d.SLA_LAYER_BLEND), c4d.DescLevel(10120, c4d.DTYPE_REAL))

HOWEVER, when I use this same DescID to add a port into the Layer/Object operator that I am working with, an empty port is created, not the Transform Angle port I want. But, if I go to manually add the correct port I want on this same operator, it is renamed to “Color Profile” and greyed out, as if it is currently being used (shown in the picture below). So, there is something missing in how I’m adding this port, either another level or a declared type with the first “c4d.SLA_LAYER_BLEND” level. I’m not sure what exactly is incorrect or missing with the adding of this port.
dev response2.PNG
We are getting closer to the answer, though.

Prevent Editable Command