I have code for 1.18.2:
 

Spoiler

public abstract class HeadItem extends ArmorItem {
	public HeadItem(EquipmentSlot slot, Item.Properties properties) {
		super(new ArmorMaterial() {
			@Override
			public int getDurabilityForSlot(EquipmentSlot slot) {
				return new int[]{13, 15, 16, 11}[slot.getIndex()] * 25;
			}

			@Override
			public int getDefenseForSlot(EquipmentSlot slot) {
				return new int[]{2, 5, 6, 2}[slot.getIndex()];
			}

			@Override
			public int getEnchantmentValue() {
				return 9;
			}

			@Override
			public SoundEvent getEquipSound() {
				return ForgeRegistries.SOUND_EVENTS.getValue(new ResourceLocation(""));
			}

			@Override
			public Ingredient getRepairIngredient() {
				return Ingredient.EMPTY;
			}

			@Override
			public String getName() {
				return "head";
			}

			@Override
			public float getToughness() {
				return 0f;
			}

			@Override
			public float getKnockbackResistance() {
				return 0f;
			}
		}, slot, properties);
	}

	public static class Helmet extends HeadItem {
		public Helmet() {
			super(EquipmentSlot.HEAD, new Item.Properties().tab(CreativeModeTab.TAB_COMBAT));
		}

		public void initializeClient(java.util.function.Consumer<net.minecraftforge.client.IItemRenderProperties> consumer) {
			consumer.accept(new IItemRenderProperties() {
				@Override
				public HumanoidModel getArmorModel(LivingEntity living, ItemStack stack, EquipmentSlot slot, HumanoidModel defaultModel) {
					HumanoidModel armorModel = new HumanoidModel(new ModelPart(Collections.emptyList(),
							Map.of("head",
									new Modelcustom_model(Minecraft.getInstance().getEntityModels().bakeLayer(Modelcustom_model.LAYER_LOCATION)).Head,
									"hat", new ModelPart(Collections.emptyList(), Collections.emptyMap()), "body",
									new ModelPart(Collections.emptyList(), Collections.emptyMap()), "right_arm",
									new ModelPart(Collections.emptyList(), Collections.emptyMap()), "left_arm",
									new ModelPart(Collections.emptyList(), Collections.emptyMap()), "right_leg",
									new ModelPart(Collections.emptyList(), Collections.emptyMap()), "left_leg",
									new ModelPart(Collections.emptyList(), Collections.emptyMap()))));
					armorModel.crouching = living.isShiftKeyDown();
					armorModel.riding = defaultModel.riding;
					armorModel.young = living.isBaby();
					return armorModel;
				}
			});
		}

		@Override
		public String getArmorTexture(ItemStack stack, Entity entity, EquipmentSlot slot, String type) {
			return "main:textures/entities/balaclava.png";
		}
	}
}

 

Looks like 1.19 doesn't have IItemRenderProperties.

Does anyone have an example or advice?

The class was renamed in 1.19 in the client refactors. Look for and override the initializeClient method from Item.

As some side-notes;

• What is up with that ArmorMaterial? At the very least, store that in a constant field somewhere, and reference it from your item.
• You don't need the HeadItem class. If you follow my first recommendation, you can reference the ArmorMaterial from your Helmet class' constructor.

sciwhiz12, thx 🧡