I have appsettings.json files in my .net project that my project is reading from. But then I´m settings some AppSettings in code. Should I just skip the appSettings.json files completely and just have it all in Pulumi code?

var App = new AzureNative.Web.WebApp("myapp", new AzureNative.Web.WebAppArgs
{
    ResourceGroupName = ResourceGroup.Apply(t => t.Name),
    Location = ResourceGroup.Apply(t => t.Location),
    ServerFarmId = AppServicePlan.Id,
    SiteConfig = new AzureNative.Web.Inputs.SiteConfigArgs
    {
        AppSettings = {
            new AzureNative.Web.Inputs.NameValuePairArgs{
                Name = "WEBSITE_RUN_FROM_PACKAGE",
                Value = BlazorCodeBlobEndpoint,
            },
            new AzureNative.Web.Inputs.NameValuePairArgs{
                Name = "ASPNETCORE_ENVIRONMENT",
                Value = Deployment.Instance.StackName.ToLower(),
            },
            //Abp.io
                new AzureNative.Web.Inputs.NameValuePairArgs{
                Name = "App:SelfUrl", //<-- So do this
                Value = MyEndpoint,
            }
        },
    },
    Tags =
    {
        { "environment", StackName },
    },
});

and not in appSettings.json

{
  "App": {
    "SelfUrl": "<https://me.com>",
   ... etc
}

And should I then get rid of every settings in appSettings.json?

You can, great example here, https://github.com/gitfool/Pulumi.Dungeon

Ok kind of lost here. Could you point me to the code part you think will help me with this?