can I return object in razor pages?
I'm guessing you have a client application, maybe JavaScript, that calls OnPostDeleteAsync(). The problem you are trying to solve, is making an AJAX call to delete a resource. But, you need the results of the delete operation to update the document loaded in the browser. See the following tutorial if you are trying make AJAX calls to Razor Page handlers and process the results.
https://www.mikesdotnetting.com/article/318/working-with-json-in-razor-pages
If the above does not answer your question, then explain what you are trying to do.