Iphone 16 won't update to IOS 26.1

Hey, I recently owned an iPhone 16 on the 18.3.2 iOS version, and I wanted to update it to iOS 26.1, so I tried on the phone and downloaded the update, but when I try to install it, "Unable to verify update. iOS 26.1 is temporarily unavailable. Try again later." So I tried with 5G instead of my casual wifi; same issue. I went to a friend's house to try with his network; same issue. I tried with iTunes on my PC; I got an error message without explanation, just a code "3194". I tried without a firewall, and I tried to change the host file, but nothing worked. I don't know what to do anymore except surrender updates.