It seems there have been an upgrade to ESP32S2 modules -
https://www.espressif.com/en/products/modules:
but i can't find any further documentation about the ECO1 changes.ESP32-S2-MINI-2 is a powerful, generic Wi-Fi MCU modules, which integrates ESP32-S2 ECO1 with improved RF performance.
"RF-performance" may be related to issues we have with our design, but I need clarification before I can insist on our HW team that they need to move to the ECO1 variant.