After searching online for the right part (WR49X10228), I found AppliancePartsPros was one of the cheapest. I ordered the part and paid a little extra for standard shipping while still paying less than the competition. A friendly CSR contacted me the next day to let me know my order had an issue with address info and corrected it over the phone. The best part? The part arrived the very next day!
I had to google a video* that showed how to replace the part and by coincidence I landed on YouTube with a video made by -- AppliancePartsPro! The explanation was thorough and well explained. I watched it once through then followed along again while completing the steps. Repair would have taken less than 30 minutes otherwise.
The project required a Philips screwdriver, a putty knife (to carefully pry frame off door), and some tape (to hold wiring in place). In the end I had a new dispenser paddle that worked even better than before, and by my estimate I saved over $200 by avoiding calling a tech. Very pleased!
* The only fault was that the video on the product page is wrong, but here'e the correct one:
https://youtu.be/AnPTsUPX39g