@GLAB No worries, was in a similar situation.. My perspective was on what the Node could be made to provide, not what could be done within Domoticz to address the requirement - eg Had heard of Dummy counters but had no experience nor understood their purpose, nor had ever used scripts.
I had been sending a logical ON/OFF as well as a cumulative total from the Node and hit the same hair-pulling scenario as yourself.
Now only the ON/OFF is sent and the short script makes the transposition within Domoticz to a dummy meter (I think kWhr) using the internal clock in Domoticz.
Have fun
No problem, I am running the nrf24 mqtt gateway on the rpi and it is working with no problem with domoticz. I choose the mqtt client gateway because I wanted to tinker around MQTT, but you could go for the ethernet gateway that is easier to manage.
You should not typ "\n"!
It means that you should press enter on your keyboard.
On Linux I saw that I have to send "\r\n" instead of "\n".
"\r\n" (Carriage return, Line feed) is the Windows return, "\n" only the Linux return.
@lrtsenar
The MySensors Libraries were designed around the nrf24l01 transceivers which have much more built in capability than a simple 433Mhz Tx/Rx pair. You can make a node which contains a nrf and 433 Rx/Tx and it can transfer messages between the MySensors architecture and common 433Mhz devices. If you are only interested in 433Mhz devices with Domoticz, see the RFLink project for more info. I believe it requires a mega to fit their libraries.