Fear not for I am walking the same path and learning much as we go. So, it’s my understanding that on the ESP32 there are three UARTS. Two of the are on the pins of our heltec devices, and UART0 is the serial debug (the 40/41 pins, 3&1 GPIOs). The third (UART1) looks, based on a schematic I found, to be hooked into the flash chip.
When I first hooked it up to do a quick test, I think that my device was also sending debug message out of pin 17 of the 16/17 fame (UART2 and also Serial2 in the code). So, I messed with the baud until I got some output. What I failed to realize was that I hadn’t set the serial module up properly. So, I thought I had it working but really, it was only the serial debug and I didn’t even try to test sending. My mistake was setting the WebUI then forgetting to restart.
If you’re only working with the environmental plugin, I don’t think you need the serial module enabled. If you want to send serial messages from the Pi to the node then yeah, that seems necessary.
And given it’s still in alpha and likely not going to be implemented any time soon, i’m going to just try to do a usb connection and use the meshtastic python lib.