We haven’t seen much demand for Svelte which has prevented us from investing more resources into supporting it further and IIRC SvelteKit requires a node server at runtime which prevents us from being able to create a project template for it since we only ever want to deploy .NET App with any SPA UI statically compiled and served from its /wwwroot folder.
If they ever document how to deploy SvelteKit Apps without node we can look at creating a project template for it if there’s enough interest in it, which you can register your interest in it by creating a feature request for it at: