It won’t show anything after 24hrs in terms of location. In find my iPhone/iPad it should then just show as offline, but it should still be listed there as one of your tracked devices.
If it had been erased, the opposite of what you see should have happened - if erased it should still show as a listed device in find my iPhone in your iCloud account, but it should not show in trusted devices (erasing breaks the tracking feature of a lost or stolen device, but does not alter activation lock, and it removes the device from trusted devices so codes no longer go to it).
So honestly I’m not sure what may have happened. I cannot think of a scenario where it would disappear altogether from find my iPhone, yet remain listed in trusted devices. An erase should result in the opposite.