Help tying a custom product to Add to Cart or Checkout

Question:
I need helpadding functionality that allows a user (after customizing a custom digital product) to preserve the resulting image and order it using the native Wix checkout feature?

Product:
Wix Editor → Add to Cart/Checkout

What are you trying to achieve:
I built (with help from ChatGPT) a custom coded product that allows a user to fill out a form, customize the input on an image, then order the size/style they want the order printed. The button “Add to Cart” will not add the item to the cart or redirect to Checkout.

What have you already tried:
Literally everything…

Additional information:
The watermarked image needs to be preserved into the checkout step and a receipt with the image the customer ordered sent to them. I also need to receive a clean copy of the image (no watermark) so I can complete the order.

The button “Add to Cart” will not add the item to the cart or redirect to Checkout.

If you did not code it exactly what should happen during the checkout-process, than nothing will happen.

You have to code a customized Check-Out-Flow including your own generated data.

I thought I’d coded it perfectly as the customizations work all the way up until the “Add to Cart” link.

The problem (from what I can tell) is that since the item is a custom object the user creates I don’t have a static product ID so the checkout link will change every time… I don’t know how to code a customized Check-Out-Flow… is that something someone could advise me on?? I’m stuck and wondering if I’m too “close” to the code and overthinking it.