This is an Origins modpack, with the origin you choose potentially completely changing the gameplay.
There are also multiple other mods in the modpack, a lot of which make pretty big changes to the game, for example:
- Complete revamps of the Nether and End dimensions, with many new biomes and items to find.
- A few performance enhancing mods, helping decrease lag substantially.
- Several client-side and ui mods that help improve the experience.
- A small quest-progression system.
I also recommend using these datapacks:
- The Caves and Cliffs world generation; Caves & Cliffs Prototype Data Pack for Minecraft Java Edition – Minecraft Feedback
- End structures; End City for "Better End" Minecraft Data Pack (planetminecraft.com)
Hopefully all this will help make the game a bit more enjoyable and give more things to do.
Also it is pretty fun to play in hardcore.