sunnyk21 a new extension would have to be created. You would likely want to create a new permission that allows permanently deleting own discussions, and alter the permissions for soft deletion so it never gets offered as an option, and maybe a few cosmetic changes to the frontend.
If you are interacting with Flarum from a script or third-party app using the REST API, you can skip soft deletion by hitting the DELETE endpoint directly, assuming you have moderation privilege.
A safer alternative would be to keep everything the same and create a scheduled task that permanently deletes soft deleted content after a given time, this way you still have some time to recover any content deleted by mistake. This can be done very crudely with SQL commands or a little more cleanly with the Flarum extension API.
