Rigidbody physics

Question

I'm currently working on a 2D game, where character is moving around a circle, but for now it's made with rb.MovePosition(), and I need to make it somehow else to detect colliders the way I want. For now my character is shaking beside the wall and simply go through it.

Here's my code:

private void Update()
{
    if (Input.GetKey(KeyCode.A))
    {
        _oldAngle = _angle;
        _angle += _speed * Time.deltaTime;
    }
    if (Input.GetKey(KeyCode.D))
    {
        _oldAngle = _angle;
        _angle -= _speed * Time.deltaTime;
    }
}

private void FixedUpdate()
{
    var position = new Vector2(Mathf.Cos(_angle * Mathf.Deg2Rad), 
    Mathf.Sin(_angle  * Mathf.Deg2Rad));
    _rb.MovePosition(_startPosition + position * _radius);
}

I’ve tried to switch rigidbody types, add rigidbody to the wall, edit colliders, nothing helps.

Any thoughts?

Character screenshot