UPDATE:

It's a late update, since this work was done in December, but I realized I did not write back.

By removing the plastic cover plate (with the interior LED) under the climate control, and accessing the rear of the panel from the glove box area (after swinging the glove box down out of the way), I was eventually able to slide the connector pictured above off of the back of the HVAC controls and disable the automatic AC function entirely. It works perfectly and I'm happy it was so simple.

While a simple process to describe, I had far more trouble physically accessing the area in question behind the dash than various videos seem to illustrate. The spaces were all smaller than they looked online (e.g. I couldn't even get a finger to the same spot where one person had filmed themselves touching and wiggling a component with their fingers) and I don't have huge hands. At the same time I also had to pull the rear defogger switch and replace the switch illumination bulb. It was handy that both jobs were in the same spot.