This is what I’m doing but the user flow is really not that great, they need to fill a form and then head to another page (wishlist) to add things to the cart 1one-by-one then go to the cart and checkout.
This is definitely a limitation. I was able to make it work but you have to get a little creative with it. I used Glide tables not Google sheet. In my solution I used one tab to calculate the values and the second tab to bring those over as a text which is what Glide requires mapped to the price field for stripe.
So what you could do is have the “product” tab, this lists the cost of the unit. Then when someone wants to buy, they can add quantity or other calculated values in the “Cart” tab do the calculations. But wait, theres more! Because values need to be “text”, you will need one last approval where the user approves the “cart” calculations (totals) and it finally pushes the “text” data to the “Checkout” which at this point is straight text. I agree it’s an added and unnecessary step from a user perspective but its the only way to carry the values over as text. Then the user can pay from there.