Some say 9999 would work for all overdue and due today.
Perhaps it is obvoius, but it will not show due e.g. next 10 days and overdue.
To acheive that, one solution that comes to my mind is to create a project one would call for instance ‘Horizon’ and make it collect automatically - via API, Zapier or Integromat to name a few - all the tasks that are due soon (so called multihoming). Then you can forget about Due date in your search and use this project ‘Horizon’ instead (& refine it to your needs).