Great work bringing this to ESPHOME 
My use case may be obvious or off-topic. And if so, I apologise, but in case it is useful to know…
This code also worked for me on my 1500TL-X, without owning a Shine Wifi module.
It works via the inverter’s COM and an off-the-shelf ESP, like the D1-Mini.
I just used the Shine-X code, with the baud rate changed back to 9600.
I have a Growatt MIC 1500TL-X
I do not have a Shine Wifi module
So I made my cable using:
- A D1 Mini
- An RS485/TTL converter
- An old USB-A cable
- The COM connector which was supplied with the Inverter
Very pleased with it.
Cheers 
