After Z-axis Rotation, character (sprite) Flip 180 degrees will not work in a 2d Game

Question

I am developing a 2d side scroller , The player is "swimming" so I was able figure out how to rotate the Z-axis of the sprite + or - depending on Y axis direction of travel If the Y axis is not used the character gradually returns to a Z axis of 0. Since the character can travel left and right, I implemented a Flip() to flip the sprite in the correct direction of travel. Interestingly, The character's sprite will not flip to the correct direction of travel until the Y axis controller is touched again, instead of immediately when the X axis is moved. The character will move in the correct X axis direction however.

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.InputSystem;

public class PlayerControl : MonoBehaviour
{
    public Animator animator;
    public Rigidbody2D theRB;

    private float inputX;
    private float inputY;

    // Z axis Rotations
    private float currentZ = 0.0f;
    private float maxZ = 15.0f;
    private float minZ = -10.0f;
    private float zRotationRate = 0.5f;

    private Vector3 rotation;

    public float moveSpeed = 7.0f;

    public bool facingRight = true;
 
    private void Awake()
    {
    }

    private void Start()
    {
        rotation = gameObject.transform.rotation.eulerAngles;
    }

    private void FixedUpdate()
    {
        // Move character
        theRB.velocity = new Vector2(inputX * moveSpeed, inputY * moveSpeed);
        currentZ = transform.rotation.z;
        RotateZ(inputY);
    }

    public void Move(InputAction.CallbackContext context)
    {
        inputX = context.ReadValue<Vector2>().x;
        inputY = context.ReadValue<Vector2>().y;
      
        Debug.LogFormat("X Axis: {0} Y Axis: {1} ", inputX, inputY);

        if (inputX > 0 && !facingRight)
        {
            Flip();
        }
        else if (inputX < 0 && facingRight)
        {
            Flip();
        }
    }

    private void Flip()
    {
        facingRight = !facingRight;
        //transform.Rotate(0f, 180, 0f);
        transform.rotation = Quaternion.Euler(0f, 180, 0f);
    }

    public void RotateZ(float inputY)
    {
        if (inputY > 0)
        {
            rotation.z = Mathf.Clamp(rotation.z + zRotationRate, minZ, maxZ);
            transform.rotation = Quaternion.Euler(rotation);
        }

        if (inputY < 0)
        {
            rotation.z = Mathf.Clamp(rotation.z - zRotationRate, minZ, maxZ);
            transform.rotation = Quaternion.Euler(rotation);
        }

        if (inputY == 0)
        {
            if (currentZ < 0)
            {
                rotation.z = Mathf.Clamp(rotation.z + zRotationRate, minZ, maxZ);
                transform.rotation = Quaternion.Euler(rotation);
            }

            if (currentZ > 0)
            {
                rotation.z = Mathf.Clamp(rotation.z - zRotationRate, minZ, maxZ);
                transform.rotation = Quaternion.Euler(rotation);
            }
        }
    }
}

Thanks for the feedback