Question about EcoFlow River Pro 600

As I don't use it in this way, I can't answer your question, so I recommend you look at the documentation on the manufacturer's website.

In fact I use the 220v socket to recharge the cell battery of my camper thanks to my ecoflow (connected to the solar panels or not). And if not, yes it's also possible to recharge the ecoflow with 12 v but it's long (while driving also with the AC plug).

I think so. The ecoflow is designed to be recharged with a 12v socket