I played 250hrs on a server with 2 other solo players. Occasionally we met up to boss fight. One of the players and I teamed up a bit to share farmed resources, but for the most part I've played about 300+ hours solo, and its been awesome. Been through the game once; now I'm mild modded (for UI/QoL and keeping it close to vanilla) and playing through again, but choosing to not use portals and swords/shields this time. I am more into the game for survival and not so much huge builds. All of the bosses/mobs are easy to take down solo, if you plan ahead.