what if apple can’t find my device after i reported it lost ? what are the nexf steps to getting a new device

Apple won't attempt to locate any device.

The only way to track it is for you to do so using Find My.

If you purchased AppleCare+ with theft and loss, file a claim under your policy if you had Find My enabled on the device, otherwise, buy a new one.

Do you have AppleCare+ with theft and loss protection?

If not, then no. You'll have to buy one.