Try the new test version its based on your registers, but make it connect through the waveshare first. See if they work (my app works with any Modbus TCP device as long as the registers are the same). Only once you confirm it works through the waveshare THEN/if you want to/ test it directly.
But just like the E v3, the D seems to have a weak TCP modbus controller so using the waveshare is probably always going to be more stable. So if it works with that one, leave it like that. The waveshare is probably multi client also so you can leave the flows you have and just run the app against the same IP.
Thanks, that doesn’t take much effort indeed 
I can confirm that this connection is stable and starts immediately. So the waveshare ensures the stable connection and your app works fine with it. Also the registers match. Out of curiosity: which registers didn’t match with your app? I’d like to check them and see what they do.
you use Register 30006 as AC Power (INT16) vs my 32202 (INT32, 2 registers).
SOC-scaling op 32104 - you use it raw I used a scale like I need on the E
I did not have the MPTT registers that provide the solar info, good find there
Just checked: 32202 returns the exact same result as 30006.
