I am glad to learn from you that Ali Express does have a facility to accommodate customer complaints. I did search the website for a means to communicate with the seller of those two batteries for my Mavic 2 Po that arrived inoperable, and whose...
Your experience with AliExpress is different than mine. However, I bought a couple of Mavic 3 batteries that no longer work after a DJI firmware update. But they worked perfectly up until then. Certainly not Aliexpress' fault. My other example...
Ali Express offers non-DJI batteries that feature greater range than the originals. Here is a link to the Phantom 3 batteries that boast of 4980 mAh as opposed to the 4480 mAh of the standard DJI battery for the Phantom 3 Standard. Bear in mind...
Sorry for your loss :-(
"... all those uncommanded pauses drain the flight battery down to dangerously low levels before I regain control and use sport mode to get the drone home."
I learned the hard way that "Sport Mode" is the wrong mode to...
Gifted wth the patient and meticulous persistence evident in this procedure you've kindly shared above, I wouldn't be surprised to learn that you are a self-made man of considerable net worth.