How to have pickups not spawn on top of the player?

I know what my problem is. The nonSpawnArea is a point and not an area/square and the if statement shouldn’t check weather the flyPosition is the nonSpawnArea, but it should check weather it is within the area. So how would I change these two things.

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

public class FlySpawner : MonoBehaviour {

	[SerializeField]
	private GameObject flyPrefab;

	[SerializeField]
	private GameObject player;

	[SerializeField]
	private int totalFlyMinimun = 12;

	[SerializeField]
	private float spawnArea = 25f;

	private Vector3 nonSpawnArea;

	public static int totalFlies;

	// Use this for initialization
	void Start () {
		totalFlies = 0;
	}
	
	// Update is called once per frame
	void Update () {

		// While the total number of flies is less than the minimum...
		while (totalFlies < totalFlyMinimun) {
			
			// ...then increment the total number of flies
			totalFlies++;

			// ...create the area in which the flies can not spawn in
			nonSpawnArea = new Vector3 (player.transform.position.x + 3f, 2f, player.transform.position.z + 3f);

			// ...create a random position for a fly...
			float positionX = Random.Range(-spawnArea, spawnArea);
			float positionZ = Random.Range(-spawnArea, spawnArea);

			Vector3 flyPosition = new Vector3 (positionX, 2f, positionZ);

			// ...check that the fly isn't spawning on top of the player
			if (flyPosition != nonSpawnArea) {
				
				// ...and create a new fly
				Instantiate(flyPrefab, flyPosition, Quaternion.identity);
			}
		}
	
	}
}

Also if you have a better way of doing this please inform me.

Assuming your player has a MeshRender component you can use the BOUNDS member, to determine the extents of the player object, in worldspace.

Then when setting the position of the new object, you can simply offset it, from the players position (or the Bound’s center), by the extents of the Bounds. I would probabaly only adjust the x and/or y values of the final position, so it remains at the same z (height) of the player.