Iphone XR keeps rebooting

My Iphone XR keeps rebooting. I did everything I can, from manually reset iphone into factory default, updating to latest ios, etc. And finally I've followed the guide to update or restoring the iPhone with iTunes, and it's also won't work. I managed to restore the iphone, but it's fail everytime the iTunes try to restore it, the iphone rebooting on the way verifying software update. And now I cannot get in to the apple logo at all, only connect device logo. I can't use my phone, I can't even restore it, too! And I found that many people on the internet couldn't fix it.

Don't give me a stupid answer like change your cable, because there is no problem at all with my cable.

And you know what, before I did all of these steps I already bring the iphone to the apple authorized service center, official distributor in my country, they asked for money and they still can't fix it!

This also happened to all my friends to their iphone XR or iphone XS.

You are really shameful for your price. This is biggest lie to customers.