In the submission form, it asks you to whether you want your project to run through Xcode(which will be run in simulator) or Swift Playground app which on a real device. Pick the second one, and it's done. Of course, if you are currently developing on Xcode, make sure it runs and works as expected in Swift Playground before submitting.

Also running issues(completely wrong result) with executions of audio processing and ML Program type CoreML models on macOS 26.3 Beta.

Here is the error and full output. ("Failed to load" appears even in successful operation, so seems like it's not the issue)