Code

Main Class (Survival.java): (Also it doesnt paste correct sometimes)
package com.pickleface.survival;

import net.minecraftforge.common.MinecraftForge;
import net.minecraftforge.fml.common.Mod;
import net.minecraftforge.fml.event.lifecycle.FMLClientSetupEvent;
import net.minecraftforge.fml.event.lifecycle.FMLCommonSetupEvent;
import net.minecraftforge.fml.javafmlmod.FMLJavaModLoadingContext;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

@Mod("survival")
public class Survival {
    private static final Logger LOGGER = LogManager.getLogger();
    public static final String MOD_ID = "survival";

    public Survival () {
        FMLJavaModLoadingContext.get().getModEventBus().addListener(this::setup);
        FMLJavaModLoadingContext.get().getModEventBus().addListener(this::doClientStuff);

        Registry.init();

        MinecraftForge.EVENT_BUS.register(this);
    }

    private void setup(final FMLCommonSetupEvent event) { }

    private void doClientStuff(final FMLClientSetupEvent event) { }
}

Registry.java:
package com.pickleface.survival;

import com.pickleface.survival.blocks.*;
import com.pickleface.survival.items.*;
import net.minecraft.block.Block;
import net.minecraft.item.HorseArmorItem;
import net.minecraft.item.Item;
import net.minecraft.util.ResourceLocation;
import net.minecraftforge.fml.RegistryObject;
import net.minecraftforge.fml.javafmlmod.FMLJavaModLoadingContext;
import net.minecraftforge.registries.DeferredRegister;
import net.minecraftforge.registries.ForgeRegistries;

import net.minecraft.item.ItemGroup;

public class Registry {

    public static final DeferredRegister<Item> ITEMS = DeferredRegister.create(ForgeRegistries.ITEMS, Survival.MOD_ID);
    public static final DeferredRegister<Block> BLOCKS = DeferredRegister.create(ForgeRegistries.BLOCKS, Survival.MOD_ID);

    public static void init() {
        ITEMS.register(FMLJavaModLoadingContext.get().getModEventBus());
        BLOCKS.register(FMLJavaModLoadingContext.get().getModEventBus());
    }

    // Horse Armor
    public static final RegistryObject<HorseArmorItem> NETHERITE_HORSE_ARMOR = ITEMS.register("netherite_horse_armor", () ->
            new HorseArmorItem(16, new ResourceLocation(Survival.MOD_ID + ":textures/entity/horse/armor/horse_armor_netherite.png"), new Item.Properties().group(ItemGroup.MISC)));

    // Plants
    public static final RegistryObject<Block> BLUEBERRY_BUSH = BLOCKS.register("blueberry_bush", BlueberryBush::new);
    public static final RegistryObject<Item> BLUEBERRY = ITEMS.register("blueberry", Blueberry::new);

    // Blocks
    public static final RegistryObject<Block> MAP_FILLER = BLOCKS.register("map_filler", MapFiller::new);
    public static final RegistryObject<Item> MAP_FILLER_ITEM = ITEMS.register("map_filler", () -> new BlockItemBase(MAP_FILLER.get(), ItemGroup.MISC));
}

Blueberry Generation (probably the problem):
package com.pickleface.survival.world.gen;

import com.google.common.collect.ImmutableSet;
import com.pickleface.survival.Registry;
import com.pickleface.survival.Survival;
import net.minecraft.block.BlockState;
import net.minecraft.block.Blocks;
import net.minecraft.block.SweetBerryBushBlock;
import net.minecraft.world.biome.Biome;
import net.minecraft.world.biome.Biomes;
import net.minecraft.world.gen.GenerationStage;
import net.minecraft.world.gen.blockplacer.SimpleBlockPlacer;
import net.minecraft.world.gen.blockstateprovider.SimpleBlockStateProvider;
import net.minecraft.world.gen.feature.BlockClusterFeatureConfig;
import net.minecraft.world.gen.feature.Feature;
import net.minecraft.world.gen.placement.FrequencyConfig;
import net.minecraft.world.gen.placement.Placement;
import net.minecraftforge.eventbus.api.SubscribeEvent;
import net.minecraftforge.fml.common.Mod;
import net.minecraftforge.fml.event.lifecycle.FMLLoadCompleteEvent;
import net.minecraftforge.registries.ForgeRegistries;
@Mod.EventBusSubscriber(modid = Survival.MOD_ID, bus = Mod.EventBusSubscriber.Bus.MOD)
public class SurfaceGen {
    // Initialize Stuff
    private static final BlockState BLUEBERRY_BUSH;
    public static final BlockClusterFeatureConfig BLUEBERRY_BUSH_CONFIG;
    private static final BlockState GRASS_BLOCK;

    // Get Blocks for gen stuff
    static {
        // Blocks
        GRASS_BLOCK = Blocks.GRASS_BLOCK.getDefaultState();

        // Generated Blocks
        BLUEBERRY_BUSH = Registry.BLUEBERRY_BUSH.get().getDefaultState().with(SweetBerryBushBlock.AGE, 3);
        BLUEBERRY_BUSH_CONFIG = (new net.minecraft.world.gen.feature.BlockClusterFeatureConfig.Builder(new SimpleBlockStateProvider(BLUEBERRY_BUSH), SimpleBlockPlacer.field_236447_c_)).tries(64).whitelist(ImmutableSet.of(GRASS_BLOCK.getBlock())).func_227317_b_().build();
    }

    @SubscribeEvent
    public static void genSurfaceDecorations(FMLLoadCompleteEvent event) {
        for (Biome biome: ForgeRegistries.BIOMES) {
            biome.addFeature(GenerationStage.Decoration.VEGETAL_DECORATION, Feature.RANDOM_PATCH.withConfiguration(BLUEBERRY_BUSH_CONFIG).withPlacement(Placement.COUNT_HEIGHTMAP_DOUBLE.configure(new FrequencyConfig(1))));
        }
    }
}

Also I know the items and blocks aren't the problem because their currently just empty items that all they have is a .group()