Yes that is correct, those are your two options and rightly so. I have a ring and have tested this because I had the same question. By setting it on Entryway (no delay) and you were to enter that room through a door that has another sensor, the motion sensor will switch automatically to delay , Giving you time to turn off the alarm.
For example let’s say you have the motion sensor installed on a porch and a stranger were to enter the porch from the outside at night. The alarm siren would go off immediately. But if you were to enter the porch from a door leading from your house into the porch that has a sensor on it, the motion sensor would switch to delay because it knows that it’s you coming from the house And the countdown warning would sound giving you time to turn off the alarm. All you have to do is test it and you’ll see. So set your motion to no delay (entryway )