I thought you were a rechargeable batteries man. Couldn't you have taken the batteries from the Elite controller and put them in the Series X controller?
Not rechargable as in AAs. Rechargable as in official Play-and-Charge battery pack that provides 30-40 hours of gameplay. I still wanted to play games, so I had to attach a USB cable to controller to charge while gaming. I just didn't have a long enough USB-C cable to continue playing while charging. So I needed something that was usable for the existing USB cable, which was the Elite V1.
The new Series controller provides USB-C connection.
Amazon product link Original: https://www.amazon.com/Xbox-One-Play-Charge-Kit/dp/B00DBDPOZ4