It’s server-based so you need to be online to play. However you can pretty much play it solo without interacting with other players (which is how I generally play it, save the occasional events and challenges).
They’ve added significant amount of content post-launch which includes new locations, NPCs, missions etc so it’s not too bad, although I would say NPCs aren’t as well put together as other Fallout games.
Not going to disagree with the tough world out there, I’m just going to suggest / ask a few things that are at least somewhat in your realm of control that might help.