I found LegionCraft and it is a OneBlock survival server where you start small and keep breaking blocks to grow your island. It feels like every block matters because you are always trying to push forward.
There are challenging bosses and when you beat them they can drop keys. You can use keys on crates to get rare loot and epic gear so fighting is actually worth it.
It also has chunk hoppers so you can automate parts of your island. The server says it is not pay to win so it is meant to feel fair while you build grind fight and loot.
