Camera should stay static on y, but rotate to keep player in frame under y: 1

The player is moving on a planar surface, which it can fall off.

I would like to make my camera follow the player, on x and z axis, but on y axis, it should stay at one “level” for example; at y = 2. And when the player falls down from the map and reaches y = 0.8, the camera should rotate down to keep it in frame.

using UnityEngine;

public class FollowPlayer : MonoBehaviour
{
    public Transform player;
    public Vector3 offset; //It's 0, 2.5, -5

    void Update()
    {
        transform.position = new Vector3(player.position.x + offset.x, offset.y, player.position.z + offset.z);
    }

What should I add to this, to make it happen?
This currently only makes the camera follow the player without moving on y axis.

What you’re looking for is probably Transform.LookAt(Vector3 target).
Transform.LookAt makes sure the forward vector of the transform is pointing towards the target