The Gen4 Roamer have built in integration. (As does the Fogstar Drift Pro, but no Sb230 option!)
The previous generation you need to use an externL shunt and use that to get datema into Victron.
It's the same with these Foxygen.... External smart shunt needed for Cerbo gx integration.
.....
External stunts will always be a bit off as they didn't account for the battery internal BMS power draw.... So the readings will drift a small bit.... But not a problem if the battery is charged regularly, as the battery BMS and shunt will reset to 100% soc.