I think the solution is simply an OTG cable fed through a notch in the faceplate!
Yes, although I’d say a cheap ESP32 board (an 8266 will do it) with an ESPHome component which then takes all the maintenance out of any firmware for that (I’ve said that before! ESPHome Component for EmonTX (ESPx & PiPicoW) - Hardware / emonESP - OpenEnergyMonitor Community).
I hooked a WEMOS Mini up and created an ESPHome Custom Component, it was OK but would end up being too slow - a proper component would do it, but that is beyond me.