Can you please add a option to request a access token for custom apps created using the new Dev Dashboard?
https://shopify.dev/docs/apps/build/authentication-authorization/access-tokens/client-credentials-grant

I have tried using the ShopifyOauthUtility.AuthorizeAsync, but it requires a code.

https://help.shopify.com/en/manual/apps/app-types/custom-apps

Starting from January 1, 2026, you can't create any more legacy custom apps. To create and manage new apps, you need to use the Dev Dashboard. This change doesn't impact any of your existing custom apps.

See related community post here