I can use the [Adafruit ESP32-S3 Feather with STEMMA QT / Qwiic - 8MB Flash No PSRAM](https://www.adafruit.com/product/5323) With a [Lithium Ion Battery - 3.7V 2000mAh](https://www.adafruit.com/product/2011) For total of 30 CHF on adafruit. https://learn.adafruit.com/adafruit-esp32-s3-feather/overview