The Audi e-Tron debuted on 17 September 2018. The Kia e-Niro debuted on 18 September 2018. The Hyundai Kona was selling in the USA on November 2017.

Are you referring to a different model? Because if we consider the e-Tron... it doesn't seem to be where this design was first seen.

The first vehicle with a regen steering wheel paddle was the 2014 Cadillac ELR, followed by the Chevy Volt and Chevy Bolt in 2016.

Their implementation of the paddle shifter was not the shiftable kind [1]. It was a lever you had to continually press to hold regen. Imagine your hand cramping up trying to keep it engaged. To this day GM has this odd implementation.

[1] https://youtu.be/6NqfESCfSUM