The game and bosses are designed to be beaten as solo, and in my opinion are actually too easy when playing multiplayer.

But the grinding, transporting ressource, crafting, etc are 100x more fun in multiplayer.

I think that the best way to play the game would be to play with a small group of players but having a good repartition of tasks, beat the boss with your group if you want, but I strongly advise to try them at least once as solo.