so how do you have fun in this game?

[Gasp]

Base building is ok until you need like 2k stone and 1k wood to do big projects..
the player vs player is awful since the weapon movesets are trash and the numbers are all off everywhere and the netcode is bad and there's no parrying and blocking with the shield is wonky at best or downright doesn't work at worst regardless if your shield is up or not

Is there end-game PVE I'm missing out on?

[Stone Spear]

no real end game- end game is you complete the build of the keystone artifact which when you use it kills you character and you go back to character creation to start from 0.

https://www.youtube.com/watch?v=Tcn59ln12wE

Not sure if recreating te character may cause bugs with the map rooms when you try to use them after using the keystone relic.

[Kaulu]

Depends on what you find fun. I'm not bothered by the resource cost for building. If anything, it feels too easy compared to 7D2D, since all iron/coal/black ice/etc nodes all respawn. The combat isn't fun...at all, for me, but I put up with it as it's needed to enslave thralls for the base, and, ultimiately, the act of building up a strong base for myself and my friends, as well as exploring the world and finding the ghosts, stone tablets, books, and all that stuff is fun. If they just changed the combat system to something that felt good(read not easy, but not bs either), I'd rate the game even higher.

Basically:
Explore the world.
Cooperate with friends to build something massive.
Grinding bosses for specific weapons from legendary chests.

These are, I would say, the reasons to play the game. Some people might love the pvp side of things, but I feel it is the weakest point in the game. If exploring and cooperating towards goals with friends isn't of interest to you, then I could see why the game wouldn't be fun for you.