Laravel 6 collections - Extract a single value from a record - eloquent

Question

I have the following collection:
$products = $this->productRepository->getByCompanyId(1)->get();
Illuminate\Database\Eloquent\Collection {#856 ▼
#items: array:1 [▼
0 => App\OrderItemProduct {#824 ▼
#table: "product"
...
#attributes: array:3 [▼
"available" => "5"
"product_name" => "Product X"
"product_id" => 1
]
....
}
]
}
I want to get the available value for a single record. I try the following which works if a record exists:
$available = $products->where('product_id','=', 1)->first()['available'];
However it throws an exception Trying to access array offset on value of type null if I try to retrieve the available value of a record that doesn't exist in the collection e.g trying to get for product_id 17:
$available = $products->where('product_id','=', 17)->first()['available'];
This was working in laravel v6 and earlier but no longer seems to work in laravel 6.17.1
Note in laravel 5.5 I was able to use the value method as follows but then that started throwing same errors as above in v 5.7 so I switched to the above method but now that no loger works either in the latest laravel version.
`available = $products->where('product_id','=', 17)->value('available');
Also when i try get why does it always return null even where record exists?
`available = $products->where('product_id','=', 1)->get('available');
Any ideas how to fix?