They don't natively, but you didn't say what victron device exactly.
There's the modbus and VE.bus and RS485 protocols.
You mean the inverter talk to a victron SLA battery, or to Cerbo GX, or ?
Sorry you lost me with that. I understand that the cerbo GX may be a Rasberry Pi device running Venus OS (Not certain on that - not my knowledgable area). I don't know what a Pi3B is but maybe a Rasberry Pi "3B" which I don't know what is. I'm more of an out of the box guy sorry can't help you.
Would like to see if you would be interested in writing code to allow a Growatt Inverter to communicate with Venus OS. I would be willing sponsor this project. Please let me know if this is somethi...