RepurposedStructures VS FTB-Chunks

Looks like either Additional Structures or Repurposed Structures

For now, I use Nullscape for generation, Repurposed Structures to add more structures, and Basic End Ores to make mining in The End worthwhile.

Repurposed Structures (Forge) (by telepathicgrunt)

I'm pretty sure they spawn in unloaded chunks. Also, if you want more structures I'd suggest using Repurposed Structures, Bygone Nether, and The Graveyard. Also, to make it easier to find these structures you can use Explorer's Compass. If you want to add more mobs I'd suggest Dragon Mounts and Lava Monsters. Also, if you don't want to lose your items when you die you should use either GraveStone or Corpse.

Forge: https://www.curseforge.com/minecraft/mc-mods/repurposed-structures

I don't have mods for everything you have asked for, but you can check some of the ones I know (1.18.2 since Terralith isn't 1.19 yet, I am unsure if it will be but I think it will) Terralith is a mod that adds very unqiue biomes without adding any new blocks to the game, there are some very interesting forests, deserts and even volcanoes Repurposed-Structures is a mod that adds new dungeons and other structures which as far as I know adds 0 blocks as well Better Village is a mod that makes villagers a lot more interesting in my opinion, I have never used it but it looks amazing from the images. Ambient Sounds adds a variety of sounds to the game and it make it feel a lot more alive Alternatively, you can use Dynamic Surroundings if you are playing 1.16.5, I like that mod a lot more

And finally, something like Repurposed Structures that adds more variants of vanilla structures to the game.

FTB Chunks - Land claiming, teams. Pretty simple.

Claim Chunk, Flan, and FTB Chunks - A big conceit of the Minestuck mod is that players can take their base from the overworld into their own little dimension, with its own map and everything. My understanding is that previous chunk claim mods interfered with this process and caused more problems than they fixed. Still re-evaluating.

FTB Chunks (Forge) (by FTB)

Chunk loaders, like https://www.curseforge.com/minecraft/mc-mods/ftb-chunks-forge or https://www.curseforge.com/minecraft/mc-mods/open-parties-and-claims or https://www.curseforge.com/minecraft/mc-mods/the-weirding-gadget etc don't require a player to be within 128 blocks.

https://www.curseforge.com/minecraft/mc-mods/ftb-chunks-forge is the mod I was talking about, maybe see it is in the pack, but it is in most skyfactory packs, so probably. https://i.latvian.dev/pc/2020-08-20_23.35.19.png this picture (directly from side curseforge site of the mod) shows the small map symbol in the upper left corner. It should be in the same position when opening your inventory (or possibly in the upper left next to your inventory slots)