@Gwil I designed a small add on board which fits the Tx4, Tx5, and upcoming Tx6 - similar to the board linked in the thread below. It’s just a simple ESP32 board with headers, and Fred and Brian did a lot of work on the ESPHome software integration for HA.
@FredM67 - yes, you can. The 1U variant of the ESP32-C3-Mini I’m using has only a U.FL connector so you must either have a feed through to an external coax socket or an antenna (which doesn’t solve the original issue). Either way, it’s quite a bit more cost and “effort” to include. Anyway, it may not even be a problem so get that testing out the way first 