fedex ! I sent iphone X last Friday and it reached to my destination in Nepal (Nepal's morning time today). Note that, I sent iphone X to Itahari, Sunsari. No issues, no hassle.
Yes, it cost me few extra bucks but it reached safe and fine.
Sent it as a gift though so that there would not be any customs issue.
for pricing, please visit a fedex location because it may vary based on your destination.