How to get real-time responses from Apple AirTags?

The AirTags are not designed to be trackers, regardless of what you want to track. If you need a "real-time" tracker, you need to get a device that relies on GPS, not Bluetooth. For cars, one popular tracker is provided by LoJack.

You can't. They are not designed to work in real-time. These tags rely on both Bluetooth and the Apple "Find My Network" to update the Apple servers (over the Internet) with the tags location on the Find My app on your iPhone. That requires a number of events to happen near simultaneously to have anything near real-time.

Even dedicated GPS trackers have a delay.

Not sure what your exact requirements are, but sure, you have 14 days, from the purchase date, to return them for a full refund. What is basically stated in Apple's marketing material is basically true ... but there are limitations with Bluetooth. Whether or not, Apple should list every possible use scenario, was their decision, which no one here has any control over ... we are not Apple employees.

If you can provide us with those requirements, we can certainly see if they are doable with the AirTags. I won't provide the details of how they work, unless you still want to give them a try.