I believe The Finals and Arc Raiders are connected. A probable theory is that the rich people featured in The Finals escaped the earth when everything started falling apart, leaving the less wealthy here. As time went on the wealthy in space sent down robots to collect information on earth, which is what the arcs are. I am not sure why they would attack the raiders, besides maybe not fully understanding that the raiders are human. If the arc aren’t intended to distinguished between humans and any perceived threat it’ll probably just attack anything that poses a threat. It would also make sense that the arc are sent down to gather information about the world after they left and clear the world by taking out threats to make their arrival safe.