How to render Toast over html dialog backdrop?

[SenouLynn]

It seems the <dialog> element sits on the 'top-level', a relatively new concept where each document has a single, top-most layer that dialog's get pumped onto. My use case involves submitting forms from within dialog modals but I can't seem to figure out how to layer the Toast on top of the modal backdrop.

Does anyone have an established pattern for rendering toasts over dialogs, or more specifically the backdrop that dialogs implicitly provide?