Player movement script based on a given symmetry

I'm trying to make a game where the movement of the second player is based on the first player's movement but with a given line of symmetry. For example, if the inputted symmetry was y=x, then when player 1 moves to the left, player 2 moves down. Problem is, I'm a novice and don't know how to do that. Can someone help me figure out what I need to change in my script to achieve this?

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class PlayerMovement : MonoBehaviour
 {
     // Start is called before the first frame update
     
     public float moveSpeed = 5f;
 
     public Rigidbody2D rb; 
     public Animator animator;
 
     Vector2 movement;
 
     // Update is called once per frame
     void Update()
     {
         movement.x = Input.GetAxisRaw("Horizontal");   
         movement.y = Input.GetAxisRaw("Vertical");   
 
         animator.SetFloat("Horizontal", movement.x);
         animator.SetFloat("Vertical", movement.y);
         animator.SetFloat("Speed", movement.sqrMagnitude);
     }
 
     void FixedUpdate()
     {
         rb.MovePosition(rb.position + movement * moveSpeed * Time.fixedDeltaTime);
     }
 }