This suggestion about recovery mode and full security let me install it. https://www.reddit.com/r/MacOSBeta/comments/1u0jrux/failed_to_install_macos_27_beta/

The Apple Watch SE does not support updating to WatchOS 11 which is why the update is not being presented to you, it's the same with my Apple Watch 5, no update to 11 available.

When you worked on your first branch, did you commit your work before creating and switching to a new branch? You could take a look at the .git directory inside your project root directory if there is anything in there but if you did not commit there is a good chance you lost your work.

You can't, your best bet is boot from an external SSD with Sonoma on it and Xcode 14, or if you have enough space left on your internal SSD to partition it and install Sonoma on it.

Sadly, While you can download the application from the AppStore itself, you cannot re-download it from AppStore Connect. And even if you could, you need the source code to do modifications. You would use Xcode to make those source code modifications and submit them back to TestFlight and the AppStore. Your only hope is either getting the source code from the original developer or start from scratch.

You could prepare an external SDD to boot into the previous version which only has Mac OS and Xcode and submit from there

I would suggest at least 16 Gb and 512Gb of disk space, and an m2 is quite sufficient

I would say you copied/paste from the web and because of that you have a lot of new lines in there. A bit of cleanup of all those empty lines might help readability. The fact that you inserted it as swift code is good.

If you grabbed the Release candidate, it has the same version number

If you have an enterprise account and it'an employees only app, you don't need to go thru Apple Appstore to distribute internally. You could put the app on the intranet and let your user download it from there.

Use TestFlight. It is made exactly for that purpose

You are definitely using a 3rd party library to decode your json code. So you might want to ask in forums related to that library where the issue is.

No You have to go thru TestFlight

Personally, I would consider at least 16Gb and 512Gb for a development machine.

This should help you: https://www.apps4world.com/add-core-data-swiftui-tutorial.html