Not trying to sway anyone from using Access but spreadsheets "excel" at performing calculations. If there are too many products or lookups you reach a point where a db becomes the better choice. In your case, filtered columns can narrow down the row to one or even several products, showing the unit weight. Reserve a cell in the top row to calculate the product weight sum. The summary formula can also be written to sum only visible filtered rows.
Or recreate in Access what you have. Just be prepared to read up on it because you need to pretty much forget what you know about Excel when it comes to db design.
If you want opinions on the suitability of your spreadsheet, post a copy of it here with a clear narrative as to what you need from a tool and we should be able to advise if you need a hammer or a saw, so to speak.
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.