/--
A constructor for monoidal categories that requires `tensorHom` instead of `whiskerLeft` and
`whiskerRight`.
-/
abbrev ofTensorHom [MonoidalCategoryStruct C]
    (tensor_id : ∀ X₁ X₂ : C, tensorHom (𝟙 X₁) (𝟙 X₂) = 𝟙 (tensorObj X₁ X₂) := by
      aesop_cat)
    (id_tensorHom : ∀ (X : C) {Y₁ Y₂ : C} (f : Y₁ ⟶ Y₂), tensorHom (𝟙 X) f = whiskerLeft X f := by
      aesop_cat)
    (tensorHom_id : ∀ {X₁ X₂ : C} (f : X₁ ⟶ X₂) (Y : C), tensorHom f (𝟙 Y) = whiskerRight f Y := by
      aesop_cat)
    (tensor_comp :
      ∀ {X₁ Y₁ Z₁ X₂ Y₂ Z₂ : C} (f₁ : X₁ ⟶ Y₁) (f₂ : X₂ ⟶ Y₂) (g₁ : Y₁ ⟶ Z₁) (g₂ : Y₂ ⟶ Z₂),
        tensorHom (f₁ ≫ g₁) (f₂ ≫ g₂) = tensorHom f₁ f₂ ≫ tensorHom g₁ g₂ := by
          aesop_cat)
    (associator_naturality :
      ∀ {X₁ X₂ X₃ Y₁ Y₂ Y₃ : C} (f₁ : X₁ ⟶ Y₁) (f₂ : X₂ ⟶ Y₂) (f₃ : X₃ ⟶ Y₃),
        tensorHom (tensorHom f₁ f₂) f₃ ≫ (associator Y₁ Y₂ Y₃).hom =
          (associator X₁ X₂ X₃).hom ≫ tensorHom f₁ (tensorHom f₂ f₃) := by
            aesop_cat)
    (leftUnitor_naturality :
      ∀ {X Y : C} (f : X ⟶ Y),
        tensorHom (𝟙 tensorUnit) f ≫ (leftUnitor Y).hom = (leftUnitor X).hom ≫ f := by
          aesop_cat)
    (rightUnitor_naturality :
      ∀ {X Y : C} (f : X ⟶ Y),
        tensorHom f (𝟙 tensorUnit) ≫ (rightUnitor Y).hom = (rightUnitor X).hom ≫ f := by
          aesop_cat)
    (pentagon :
      ∀ W X Y Z : C,
        tensorHom (associator W X Y).hom (𝟙 Z) ≫
            (associator W (tensorObj X Y) Z).hom ≫ tensorHom (𝟙 W) (associator X Y Z).hom =
          (associator (tensorObj W X) Y Z).hom ≫ (associator W X (tensorObj Y Z)).hom := by
            aesop_cat)
    (triangle :
      ∀ X Y : C,
        (associator X tensorUnit Y).hom ≫ tensorHom (𝟙 X) (leftUnitor Y).hom =
          tensorHom (rightUnitor X).hom (𝟙 Y) := by
            aesop_cat) :
      MonoidalCategory C where
  tensorHom_def := by intros; simp [← id_tensorHom, ← tensorHom_id, ← tensor_comp]
  whiskerLeft_id := by intros; simp [← id_tensorHom, ← tensor_id]
  id_whiskerRight := by intros; 

Proof state:
C✝ : Type u
𝒞 : Category.{v, u} C✝
inst✝³ : MonoidalCategory C✝
C : Type u
inst✝² : Category.{v, u} C
inst✝¹ : MonoidalCategory C
U V W X Y Z : C
inst✝ : MonoidalCategoryStruct C
tensor_id : autoParam (∀ (X₁ X₂ : C), 𝟙 X₁ ⊗ 𝟙 X₂ = 𝟙 (X₁ ⊗ X₂)) _auto✝
id_tensorHom : autoParam (∀ (X : C) {Y₁ Y₂ : C} (f : Y₁ ⟶ Y₂), 𝟙 X ⊗ f = X ◁ f) _auto✝
tensorHom_id : autoParam (∀ {X₁ X₂ : C} (f : X₁ ⟶ X₂) (Y : C), f ⊗ 𝟙 Y = f ▷ Y) _auto✝
tensor_comp :
  autoParam
    (∀ {X₁ Y₁ Z₁ X₂ Y₂ Z₂ : C} (f₁ : X₁ ⟶ Y₁) (f₂ : X₂ ⟶ Y₂) (g₁ : Y₁ ⟶ Z₁) (g₂ : Y₂ ⟶ Z₂),
      f₁ ≫ g₁ ⊗ f₂ ≫ g₂ = (f₁ ⊗ f₂) ≫ (g₁ ⊗ g₂))
    _auto✝
associator_naturality :
  autoParam
    (∀ {X₁ X₂ X₃ Y₁ Y₂ Y₃ : C} (f₁ : X₁ ⟶ Y₁) (f₂ : X₂ ⟶ Y₂) (f₃ : X₃ ⟶ Y₃),
      ((f₁ ⊗ f₂) ⊗ f₃) ≫ (α_ Y₁ Y₂ Y₃).hom = (α_ X₁ X₂ X₃).hom ≫ (f₁ ⊗ f₂ ⊗ f₃))
    _auto✝
leftUnitor_naturality : autoParam (∀ {X Y : C} (f : X ⟶ Y), (𝟙 (𝟙_ C) ⊗ f) ≫ (λ_ Y).hom = (λ_ X).hom ≫ f) _auto✝
rightUnitor_naturality : autoParam (∀ {X Y : C} (f : X ⟶ Y), (f ⊗ 𝟙 (𝟙_ C)) ≫ (ρ_ Y).hom = (ρ_ X).hom ≫ f) _auto✝
pentagon :
  autoParam
    (∀ (W X Y Z : C),
      ((α_ W X Y).hom ⊗ 𝟙 Z) ≫ (α_ W (X ⊗ Y) Z).hom ≫ (𝟙 W ⊗ (α_ X Y Z).hom) =
        (α_ (W ⊗ X) Y Z).hom ≫ (α_ W X (Y ⊗ Z)).hom)
    _auto✝
triangle : autoParam (∀ (X Y : C), (α_ X (𝟙_ C) Y).hom ≫ (𝟙 X ⊗ (λ_ Y).hom) = (ρ_ X).hom ⊗ 𝟙 Y) _auto✝
X✝ Y✝ : C
⊢ 𝟙 X✝ ▷ Y✝ = 𝟙 (X✝ ⊗ Y✝)

Next tactic:
simp [← tensorHom_id, tensor_id]