About 2 years ago, me and some friends produced a small batch of similar watches, but we used a different LiPo connector and USB-C to make it thinner and then w

About 2 years ago, me and some friends produced a small batch of similar watches, but we used a different LiPo connector and USB-C to make it thinner and then we could get the cases down to 11mm thickness, which is comparable to the thinnest Apple Watch. So in general, ESP32 and e-ink is a pretty great basis to start from. Since this appears to be open source, you could, in theory, apply these modifications to their design and then produce your own batch of thin e-ink watches... If you do, please send them a pull request ;)