Hello,
Despite the fact that assigning deferred start dates on next actions is counterproductive to the GTD methodology, I find it really usefull in order to unclutter my lists.
Assuming you are not already using Priority level in Reminders, in your Smart Lists, you can simply add a “No priority” filter.
In order to hide a task until a certain date, add the #Defer tag and set the deadline field.
How does it work? The Shortcut assigns a low priority level to the tasks if the date hasn’t passed yet. Once the deadline is reached, the Shortcut removes the priority level and the date.
Create a personal automation : « when Reminders is opened, Run Shortcut … »
Shortcut link
Best regards