Trying to make a sprite flip based on walking direction as well as camera position

Hey! :)

I'm trying to flip a sprite in a 3D environment. It should flip depending on the camera angle (the camera can rotate) and it should also flip depending on walking direction.

I have this script which have two variables (lastPosition to track when it moves, and fyRot is camera position) that I can't get to work at the same time. If I remove the one of them, the other one work. But if I both have them together, only the fyRot seem to flip the sprite.

Would really appreciate any help with this, I'm quite new to coding! Been trying to fix it for over a week. My best guess is that the camera flip overrides the lastPos flip. But haven't been able to figure out how to fix that.

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class flippety_flippety : MonoBehaviour
 {
     [SerializeField] SpriteRenderer spriteRenderer;
     public static bool flipX;
 
 
     Vector3 lastPos;
     public Transform obj; // drag the object to monitor here
 
     public float threshold = 1.0f; // minimum displacement to recognize a 
 
 
     void Start()
     {
         SpriteRenderer spriteRenderer = GetComponent<SpriteRenderer>();
         lastPos = obj.position;
     }
 
 
 
 
     void Update()
     {
         float fYRot = Camera.main.transform.eulerAngles.y;
 
 
         Vector3 offset = obj.position - lastPos;
         if (offset.z > threshold)
         // code to execute when Z is increased
         {
             // update lastPos
             lastPos = obj.position;
             if (flipX == false)
             {
                 
                 spriteRenderer.flipX = true;
                 Debug.Log("TestingTrue");
             }
             else if (flipX == true)
             {
                
                 spriteRenderer.flipX = false;
                 Debug.Log("TestingFalse");
             }
 
         }
         // code to execute when Z is getting smaller
         else
         if (offset.z < -threshold)
         {
             // update lastPos
             lastPos = obj.position; 
 
             if (flipX == false)
             {
                 
                 spriteRenderer.flipX = true;
                 Debug.Log("TestingTrue2");
             } else if(flipX == true)
             {
                 
                 spriteRenderer.flipX = false;
                 Debug.Log("TestingFalse2");
             }
 
         }
 
 
 
 
 
         if (fYRot >= 180)
         {
             if (flipX == false)
             {
 
                 spriteRenderer.flipX = true;
                 Debug.Log("TestingTrue3");
             }
             else if (flipX == true)
             {
 
                 spriteRenderer.flipX = false;
                 Debug.Log("TestingFalse3");
             }
         }
         else if (fYRot >= -180)
         {
             if (flipX == true)
             {
 
                 spriteRenderer.flipX = true;
                 Debug.Log("TestingTrue4");
             }
             else if (flipX == false)
             {
 
                 spriteRenderer.flipX = false;
                 Debug.Log("TestingFalse4");
             }
         }
     }
 }