Take the example of an alarm clock using an input_datetime to trigger an automation. Why can’t I trigger the automation with an offset from the input_datetime, using the value from an input_number rather than a fixed offset - i.e. 15 minutes before the alarm goes off, turn on the coffee machine; 30 minutes after my preset bedtime, turn down the heating.
To be clear: you are asking for the time trigger to support entities with a numeric value (or templates) in the offset option?
+1