Same here. Unfortunately, if you use Xcode to develop for iOS, then Apple basically forces you to install macOS 27 to be able to develop for the new iPhones. The iPhone 18 Pro requires Xcode 27, and Xcode 27 won't run on Sequoia.

If anyone knows how to make the iPhone 18 Pro work with Xcode 26 on Sequoia, and in turn with iOS 27, I (and I'm sure many other people) would be very happy to hear how!

This is how Apple have forced Mac upgrades for the last 20 years, there is no way round it other than to comply and buy yourself a new Mac.