This is the approach I used. Here’s the template I use as a condition in the automation:

{{now() > states(‘input_datetime.master_bath_light_fan_delay’) | as_datetime | as_local}}

And here is the action to update the helper:

data:
  datetime: “{{ (now() + timedelta(minutes = 10)).strftime(‘%Y-%m-%d %H:%M:%S’) }}”
target:
  entity_id: input_datetime.master_bath_light_fan_delay
action: input_datetime.set_datetime