My ground checker only works... sometimes

so basically it works fine on flat ground but if it interacts with a sloped tile like a rock it only has a 50/50 chance of letting my player jump, any help would be greatly appreciated.

 void Start()
 {
     rb = GetComponent<Rigidbody2D>();
     anim = GetComponent<Animator>();
 }

 // Update is called once per frame
 void Update()
 {
     Move();
     Jump();
     CheckIfGrounded();
 }
 void Move()
 {
     float moveInput = Input.GetAxisRaw("Horizontal");
     rb.velocity = new Vector2(moveInput * speed, rb.velocity.y);
    
     if (moveInput == 0)
     {
         anim.SetBool("isRunning", false);
     }
     else
     {
         anim.SetBool("isRunning", true);
     }

     if (moveInput < 0)
     {
         transform.eulerAngles = new Vector3(0, 180, 0);
     }
     else if (moveInput > 0)
     {
         transform.eulerAngles = new Vector3(0, 0, 0);
     }
 }

 void Jump()
 {
     if (Input.GetKeyDown(KeyCode.Space) && isGrounded)
     {
         rb.velocity = new Vector2(rb.velocity.x, jumpForce);
         anim.SetTrigger("Jump");
     }
 }

 void CheckIfGrounded()
 {
     Collider2D collider = Physics2D.OverlapCircle(isGroundedChecker.position, checkGroundRadius, groundLayer);
     if (collider != null)
     {
         isGrounded = true;
         anim.SetBool("IsJumping", false);
     }
     else
     {
         isGrounded = false;
         anim.SetBool("IsJumping", true);
     }
 }

}