How do I compare the same int in two different GameObjects?

It seems you misunderstand how GameObjects work.

A GameObject is just an entity in a scene. By itself, it is pretty much useless, but its purpose is to hold Components, which are various objects you attach to a GameObject. Transform is a Component, it represents the GameObject's position in the scene space, a Sprite is a Component, a Renderer, a RigidBody... anything you attach to a GameObject is a Component. That includes the scripts you wrote.

So let's say you have a script with a public int attribute :

 public class MyScript : 
 {
     public int myInt = 0;
 }

What happens when you attach it to a GameObject (myGameObject) ? It means that myGameObject will have a Component that is an instance of MyScript. But myGameObject won't magically get a myInt attribute, you cannot access this value directly from the GameObject. You need to get a reference to the MyScript Component that is attached to myGameObject, and then get the myInt attribute of said Component.

So here's your script with your two GameObjects :

 public class CompareInts : MonoBehaviour
 {
     public GameObject go1;
     public GameObject go2;
 }

After you assign them in the scene, you have references to your two GameObjects, but you still can't read the myInt values. So the next step is to get references to their MyScript Components. For this, you need to use GetComponent.

So in MyScript, write :

 private void Compare()
 {
     MyScript myScript1 = go1.GetComponent<MyScript>();
     MyScript myScript2 = go2.GetComponent<MyScript>();
 
     if (myScript1.myInt == myScript2.myInt)
     {
         // Whatever.
     }
 }

And then you have it, you got your two ints and you can compare them.