WTH Why can't I easily offset an input_datetime based automation

[tom_l]

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WTH Can we have an offset on date/time helper trigger in automations

A time trigger allows you to use a date/time helper instead of a hardcoded time. Would it be possible to add an optional offset (+/-) to this, in the same way as sunrise/sunset does. Could be used in a situation like an alarm time (the date/time helper) and the automation can be triggered to run, say, 15 minutes before the date/time to turn something on to be ready for alarm time. This way changing the alarm time helper adjusts the ‘alarm’ automation and the ‘turn on before alarm’ automation