It’s a great question and I don’t know the full answer yet. Note above that I was confused about what amps I should be seeing and what I’m not seeing.
The fridge and inverter are not on this circuit and have a much more appropriately sized wire. I think this is only “in-line” with the circuits that ground through the van frame and include anything connected to my rear fuse box.
This includes: solar, lights, and poptop lift (FYI - about 14amps max when starting to lift), water pump, and a stubbed out line intended for future rear shower if we ever decide manual isn’t good enough. So maybe not as bad as it looks? It kinda makes sense not to run the inverter through the shunt as it would pull too much amps anyway (shunt is 100a). But I think the fridge should be monitored.
In this photo you can see the smaller ground line that is on this shunt and then the larger line going to the inverter and fridge.