There is nothing weird in MoltenVK, it's just another library that calls the Metal API.

MoltenVK doesn't use any private API, and it's already used on both the iOS and macOS App Store. You shouldn't have any issue.

MoltenVK simply calls the Metal API in the end, there isn't any issue at all from an App Store review point of view. The main issues are that it adds an overhead over calling Metal directly, and that it might be missing some of the newer features available in Metal, but it's up to you and to what you actually needs are whether it's could work for your app or not.

@available requires that the symbols in the code block are available in the sdk. If you are using a previous sdk, you have to fall back to the good old C preprocessor and disable the code block. @available is not a way to make it possible to compile code that requires a newer sdk on an older Xcode version.

Try to set a constrain on the width.

Xcode ships only one SDK per platform. Xcode 14 still has the old macOS 12 SDK, while the beta had the macOS 13 SDK. This is because, just like last year and the year before, the new macOS version is still in beta, and Apple doesn't ship a beta SDK in a public release. The macOS 12 SDK allows to deploy to 10.9, the 13 SDK that was in the beta and that will be in Xcode 14.1 will allow only to deploy to 10.13 and higher.

Xcode 14 doesn't ship the macOS 13 sdk. All these changes that were in the Xcode 14 beta will be in Xcode 14.1.

C++ doesn't understand Objective-C classes, you have to use Objective-C++ (and rename the files to .mm)

Swift ABI got stable in 10.14.4, this means that those libraries are now bundled with macOS. Probably you set the deployment target to a version older than 10.14.4, so Xcode bundles the Swift libraries, but only for Intel because the first macOS version for arm was 11, and it already includes those libraries.

As far as I know OpenGL is still deprecated, same as before. It hasn't been removed.

Because it's an private class of the NSAttributeString class cluster, and there shouldn't be any difference in the public interface.

Yes, code sign first then notarise. There are some useful topics here on this forum too: https://developer.apple.com/forums/thread/707080 https://developer.apple.com/forums/thread/707377

The way setCanDrawConcurrently works is that AppKit calls your drawRect method in another thread. And that's it, it doesn't mean you can safely draw things on yet another thread different from the calling thread.

That's the NSNotFound constant..

That seems unrelated to NSView setCanDrawConcurrently property. Either try to use setCanDrawConcurrently directly, it finally works on 10.14 and later, or do what was recommended in that stackoverflow answer.