How to create a fixed joint when two objects collide?

Hello, for a project I am working on (Unity 2020.1.5f1 for Oculus Quest) I need to have two objects that initially move independently of one another, but move together once they collide. My project was initially using VRTK v3, which has a feature that is supposed to do what I want it to do; however, the VRTK v3 package is completely non-functional on my computer (even when the files are present in the project) and the files self-delete whenever the Unity editor is restarted, so I am using Unity's XR Interaction Toolkit instead for the interactions I need (which does NOT come with the feature I need to make this). I am trying to write a script that creates a fixed joint on collision, but so far, nothing works. It seems that the game is not registering when the two objects collide. This is the latest script I have attempted:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class SnapScript : MonoBehaviour
 {
     private void OnCollisionEnter(Collision collision)
     {
         if(collision.gameObject.GetComponent<Rigidbody>()!=null)
         {
             gameObject.AddComponent<FixedJoint>();
             gameObject.GetComponent<FixedJoint>().connectedBody = collision.rigidbody;
         }
     }
     // Start is called before the first frame update
     void Start()
     {
         
     }
 
     // Update is called once per frame
     void Update()
     {
         
     }
 }

Any help getting the desired behavior would be appreciated; I've so far gotten no help and nothing I've found seems to get this working. Thanks.