they only show up X hours after the were last in contact with the phone
"If your AirPods, AirPods Pro, or AirPods Max are out of range or need to charge, you might see their last known location, "No location found," or "Offline." You also won't see the location for your AirPods or AirPods Pro if they're inside their Charging Case. You can see AirPods Max in Find My for up to 18 hours inside their Smart Case. Outside of their Smart Case, you can see them for 72 hours. Learn more about AirPods Max battery life. "
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How to find your lost AirPods, AirPods Pro, or AirPods Max - Apple Support