According to the release notes it currently requires Apple Intelligence to be enabled at system level for it to work in Xcode: https://developer.apple.com/documentation/xcode-release-notes/xcode-26-release-notes

That's a bit strange, normally it's the other way around, dSYM being included in release build and not in debug. Check your schemes and make sure Archive is using Release config. Then under your project's build settings select All and Levels instead of Combined. Make sure DWARF with dSYM is selected for your release builds and that Strip Debug Symbols During Copy is set to No. Is your project relatively new? Does it have an Info.plist?

If the people you spoke to are unable to help you then you're unlikely to find a solution here. This forum is mainly frequented by other developers in the program and the occassional Apple engineer whose expertise is unlikely to be of use for this issue. I'm afraid your best bet is still to try and resolve your payment issue with Developer Support. It's not uncommon for there to be restrictions on available payment methods to prevent fraud. As a long shot: if you are able to make purchases in the App Store you could try to download the Developer app, log into your developer Apple Account and use the IAP option to enroll in the program that way.

Double check the mail server that handles your email. It has happened in the past that emails from Apple's Developer Support didn't properly get routed to the recipients inbox due to mail server misconfigurations. If at all possible see if there is an email tracing tool available to see what happened to emails if anything at all.

The implementation details of how Xcode works with iPhones have changed. Apple moved away from using DeveloperDiskImage.dmg and signature files since iOS 17. I doubt anyone here is able to help you because what you aim to do strays far from the main supported path and I doubt the forum moderators will allow people to share Apple's copyrighted proprietary materials in ways not officially supported. Your best bet is to update to the latest Xcode version your MacBook supports and if that Xcode version doesn't support your iOS 18.5 device then I'm afraid your best option is to ugprade your developer machine. You might be able to find some creative GitHub project that might try to provide a solution for your conundrum, but there be dragons and they'd be much better suited to help you with any questions you might have about the files Xcode needs.

Hello Dayton, I'm sorry to hear you're running into issues. This forum will probably not be the place where you'll find solutions however. This is a forum for developers to discuss matters related to software development for Apple's devices and Apple doesn't monitor these forums. It seems like you've already been in contact with a support representative and if they state it's being worked on despite not being able to provide more detailed information then that's as good as it gets I'm afraid.