The Samsung SmartThings arrival sensor sells for $20 on Amazon, And it is uniquely processed by smartthings.
There isn’t anything that can do something when it goes out of range because, well, it’s out of range.
So instead, you have to have a polling automation That marks it as “away” when it hasn’t been reachable for some fixed period of time. That’s how smartThings does it with their arrival sensor.
If you want to create your own device to do something similar, you can use anything at all that has a regular check in And then mark it as absent once it misses a couple of check ins. But you’re going to run into all the same issues that you run into with the official arrival sensor. But, sure, there are other options.
See The community FAQ: