Battery was new in July 2019.

I did not do the voltage measurements in post #22 as I'm not sure how to do it. As mentioned before, I'm not even close to being a mechanic. I don't have a service manual and am not even sure I could properly read it. I'm trying to test what I can and just relaying the results to all of you for feedback, which I appreciate very much. I'm sorry I can't provide information that would be more helpful.

I did do the test of the pulse module as Pizzaguy suggested (see post #39). Before I did this I was not hearing the loud click at the starter. After I did it I tried to start the car normally, with the key, and heard the same loud click. I don't think I was getting the click before. Why would it start now? Seems to me that Pizzaguy's explanation of starter or solenoid failure makes sense.