MBUS configuration on Raspberry Pi Zero2W with MerlinGerin PM710 analyser. Connection error.

Hello!
I have this little plan to do a remote reading over Wifi to the MerlinGerin PM710 network analyser.

So I have an RPi Zero2W and have connected it via UART to this analyser. Here is the first problem, because after all the analyser talks over RS485. Well, it's just that mine has a beaten transciever and I connected directly to the UART output from the processor - here just converting the 3v3 levels to 5V took care of the communication issue.
Unfortunately, I'm having trouble getting the parameter readout to work. I have NodeRed installed on the raspberry and a Dashboard added to display the readings and a plugin to handle MBUS.
https://flows.nodered.org/node/node-red-contrib-m-bus
Like this. On my RPI, the UART port is called ttyS0 and when I configure it with the "serial" tile I can feed the character stream normally and it is actually sent physically - that's what I've determined, so it physically works.

On the other hand, when I put the "M-BUS" tile and configure it with the same port "SERIAL/ttyS0). I get the error:
Error while connecting No connection possible to MBus Serial port /dev/ttyS0

I haven't the faintest idea how to even begin to troubleshoot this. Is there any way to see why it can't open the port?

This I will answer myself. As usual, not an observation. The MBUS problem remains unsolved - indeed this nod does not open the port. The cause remains unknown.

However, I found the PDF for the meter and there it is already clearly stated that it talks with MOD-bus and not M-bus. I applied the relevant Modbus-read in the Node-Red from the paspberry and I have communication.