FIX FOUND:
After less than a year, my chair started making a creaking sound when I leaned back. After about a month of this, the tilt back mechanism stopped locking and the back was in free motion. Essentially, the chair seemed to be broken.
The fix (so far, so good):
There is bolt covered with a black plastic cap on the opposite side of the tilt mechanism handle. Using a wrench, I tightened it. Not super tight, just snugged it up.
Day 1: IT WORKED! I'm sitting in the chair typing this. The tilt mechanism is working.
FYI: The hight adjustment strut can be replaces if need be. It's a pain to remove it but it is replaceable.
Bambookenoh. my. GOD.
Thank you. That was shockingly easy solution for this infuriating issue. Thank you for making this comment. This is the only place on the internet I found a solution.
I love you. I honor you.