-- Module: Mathlib.Condensed.Light.InternallyProjective
Goal:
R : Type u
inst : CommRing R
P : LightCondSet
A B : LightCondMod R
e : A ⟶ B
he : Epi e
S : LightProfinite
g :
  tensorObj (𝒞 := ObjectProperty.FullSubcategory.category (Presheaf.IsSheaf (coherentTopology LightProfinite)))
      (obj (free R) S.toCondensed) (obj (free R) P) ⟶
    B
S' : LightProfinite
π : S' ⟶ S
hπ :
  Function.Surjective (α :=
    (fun
          (X :
            CompHausLike fun (X : TopCat.{u}) ↦
              TotallyDisconnectedSpace.{u} (↑X : Type u) ∧ SecondCountableTopology.{u} (↑X : Type u)) ↦
        (↑(X.toTop (P := fun (X : TopCat.{u}) ↦
              TotallyDisconnectedSpace.{u} (↑X : Type u) ∧ SecondCountableTopology.{u} (↑X : Type u))) :
          Type u))
      S')
    (β :=
    (fun
          (X :
            CompHausLike fun (X : TopCat.{u}) ↦
              TotallyDisconnectedSpace.{u} (↑X : Type u) ∧ SecondCountableTopology.{u} (↑X : Type u)) ↦
        (↑(X.toTop (P := fun (X : TopCat.{u}) ↦
              TotallyDisconnectedSpace.{u} (↑X : Type u) ∧ SecondCountableTopology.{u} (↑X : Type u))) :
          Type u))
      S)
    (⇑(ConcreteCategory.hom (FC :=
          fun
            (x1 x2 :
              CompHausLike fun (X : TopCat.{u}) ↦
                TotallyDisconnectedSpace.{u} (↑X : Type u) ∧ SecondCountableTopology.{u} (↑X : Type u)) ↦
          C((↑(x1.toTop (P := fun (X : TopCat.{u}) ↦
                  TotallyDisconnectedSpace.{u} (↑X : Type u) ∧ SecondCountableTopology.{u} (↑X : Type u))) :
              Type u),
            (↑(x2.toTop (P := fun (X : TopCat.{u}) ↦
                  TotallyDisconnectedSpace.{u} (↑X : Type u) ∧ SecondCountableTopology.{u} (↑X : Type u))) :
              Type u)))
          (CC :=
          fun
            (X :
              CompHausLike fun (X : TopCat.{u}) ↦
                TotallyDisconnectedSpace.{u} (↑X : Type u) ∧ SecondCountableTopology.{u} (↑X : Type u)) ↦
          (↑(X.toTop (P := fun (X : TopCat.{u}) ↦
                TotallyDisconnectedSpace.{u} (↑X : Type u) ∧ SecondCountableTopology.{u} (↑X : Type u))) :
            Type u))
          π) :
      (a :
          (fun
                (X :
                  CompHausLike fun (X : TopCat) ↦
                    TotallyDisconnectedSpace (↑X : Type u) ∧ SecondCountableTopology (↑X : Type u)) ↦
              (↑X.toTop : Type u))
            S') →
        (fun
              (X :
                CompHausLike fun (X : TopCat) ↦
                  TotallyDisconnectedSpace (↑X : Type u) ∧ SecondCountableTopology (↑X : Type u)) ↦
            (↑X.toTop : Type u))
          S)
g' :
  obj (free R)
      (tensorObj (𝒞 := ObjectProperty.FullSubcategory.category (Presheaf.IsSheaf (coherentTopology LightProfinite)))
        S'.toCondensed P) ⟶
    A
hh :
  CategoryTheory.Functor.map (free R) (lightProfiniteToLightCondSet.map π ▷ P) ≫
      Iso.inv (μIso (free R) S.toCondensed P) ≫ g =
    g' ≫ e
⊢ Eq (α :=
    tensorObj (𝒞 := ObjectProperty.FullSubcategory.category (Presheaf.IsSheaf (coherentTopology LightProfinite)))
        (obj (lightProfiniteToLightCondSet ⋙ free R) S') (obj (free R) P) ⟶
      B)
    (CategoryTheory.Functor.map (lightProfiniteToLightCondSet ⋙ free R) π ▷ obj (free R) P ≫ g)
    (((Iso.hom (μIso (free R) S'.toCondensed P) ≫
          CategoryTheory.Functor.map (free R) (lightProfiniteToLightCondSet.map π ▷ P)) ≫
        Iso.inv (μIso (free R) S.toCondensed P)) ≫
      g)

Tactic:
simp only [comp_obj, Functor.comp_map, μIso_hom, ← μ_natural_left, μIso_inv, assoc, μ_δ,
      comp_id]

Premises used: CategoryTheory.Functor.comp_obj, CategoryTheory.Category.assoc, CategoryTheory.Category.comp_id, CategoryTheory.Functor.Monoidal.μIso_hom, CategoryTheory.Functor.Monoidal.μIso_inv, CategoryTheory.Functor.LaxMonoidal.μ_natural_left, CategoryTheory.Functor.comp_map, CategoryTheory.Functor.Monoidal.μ_δ