There’s always going to be a need to adjust either the expectations of the website software to accommodate the spreadsheet or adjust the spreadsheet to accommodate the expectations of the website software, whichever one you choose.
Without seeing the spreadsheet, it’s difficult to speculate which is the best option in your case. Remember, though, that Excel is pretty powerful and you can apply changes against many rows at once.
All the ecommerce solutions I can think of would look for named columns in the spreadsheet and ignore other things in there, which should make life easier. Use (text manipulation) formulae!
Presumably, with 7000 products (did we work out if this was products or product options in the end?) you will need to provide a fairly good environment in which someone can manage the products, prices etc.
Rachel