I have had content blockers in the Mac App Store for years. Ever since moving to Sonoma, doing a clean build or archive in XCode deletes the extension from Safari settings since it never gets into the built app. The only way for me to get it back is to remove the DerivedData and target, reboot, and create a target with a different name. That works and stays around in Safari settings as long as I only build and don't clean. However, a clean or an archive removes it again.
Restoring a version of the project from Time Machine that was posted to the App Store weeks or months ago doesn't work. However I can download the version of the app in the App Store, and it works, but I can't build it now from the source code that was used to build that version without going through the above process. Moving from Sonoma 14.7.1 to 14.7.2 didn't work. I would move to Sequoia if I had reason to believe that would work, but I don't.
Safari 18.2, Sonoma 14.7.2, 32GB, 2.2 GHz 6-Core Intel Core i7