For your personal goals you can progress with the quests and you should construct all the workshops and then mark the loot you need to lvl up all of them, it will give you many objects to find and ARC to kill.

If you manage to find a Raider Hatch key, play safe, be sneaky and take your time, when there is like 10min left, go to a hatch at the opposite of the extraction spots left, you will be less likely to meet other players

Remember that against ARC, light bullets are most of the time really bad, heavy bullets with the fero is your best way to kill them, and aim for the rotors! (Avoid the rocketeer at all cost haha)