It’s very much a single player game. You and your buddies can join each other and play around. These time limited events called expeditions you’re likely to see some other players just because the events allow players to be in the right place (very condensed) at the right time (over the course of two months).

If you don’t even want to see people turn multiplayer off and the only evidence you’ll see is planet/flora/fauna discovered by player.

As for the normal game we all share the same universe with most of the population (my self included) in the first galaxy but it’s so huge you’re super (and I can not emphasize this enough) SUPER SUPER unlikely to run into another player

Because it’s one universe there’s not a my world your world like Minecraft for example, so if you join your friend, you can still fast travel to your base (there’s a portal fast travel system between bases discovered/landed space stations

Also there’s crossplay!

Oh a quality of life tip, you only need to build a base computer (item that lets you claim the build area) to teleport back, not the portal, the portal only allows you to travel from the base

The amount of bases with nothing in them becuase I’ve been meaning to come back to it later and build

If you like text based story (no spoken dialogue) that how nms is delivered

There’s a few main stories and if i remember right the stories themselves don’t overlap but they do overlap in kind of a big picture way. Hard to describe it without spoilers

Some criticism tho is after 20-30 planets you start to see some repetition but the last update worlds part 1, added some stuff like actual floating islands new animals and better terrain generation but it doesn’t bother me too much

This kinda turned into a ramble but hopefully this helps

And here’s the NMS website