Has to be Pakistan.
You're right. I have been watching US & Brit C17’s since this started on ADSB exchange.com coming out of Dubai. They then turning north to transit north through Pakistan.
Once they are a couple of hundred miles inside Paki airspace they turn their transponders off and go dark. Just today noticed a K135 tanker going north which means fighters.
Oddly I have seen Hungarian and Spanish C17’s in the evening (PDT) so we are getting help.
Also there is some occasional US traffic through Iran but not very much.