We're in the process of moving our 10+ year old, in-house made webstore to a shopify webstore, and we've got it mostly up and running, but we are running into some issues. Firstly we can't figure if or how we can edit when the product was made/added to the store. When we were moving our existing products to the store, we didn't realize that that would be seemingly only way the store determines the date of the product. We would like to be able to use the newest-oldest sorting feature , but it's currently a jumbled mess because we didn't add the products in their release order.
Similarly, because we are new shopify store, our Sort by Bestsellers option doesn't reflect what our actual bestsellers are.
Is there a way to bring over our old sales data so that our bestsellers are more accurate? Also how can we modify when our products were added and/or published so they can also be accurately sorted?
There is an app called Excelify that allows you to sort out your product created at dates and I think you'll also be able to import you past orders (although I've never tried that one).
Basically install the app, do an export of all your products and change the 'date created at' field for each product as you want and then do an upload.
For orders have a look at this article https://excelify.io/whats-new/shopify-orders-import/ I think you should be able to do what you need.
There is a fee for the app but you only need to pay for it/keep it for as long as you need it.