Thank you for the answer, but my project is in C#… so I cannot use that…
I ended up with finding a solution, not perfect but a working solution…
string url = "https://admin.shopify.com/store/" + domain + "/products/" + shopifyProductId.ToString ("");
// Because the App opens in a Frame inside shopify, we need to pass the parameter "_top"
await jsRuntime.InvokeAsync
With this solution, the url request jumps outside the IFrame used by shopify to display the App, and it works.