I built an app using metal compute shaders to capture 4d gaussian splat video for the iphone. Took about two months to get it running in realtime with good compression and quantisation.

Apple have now rejected it 5 times (it takes them a week to reply each time, so that's 5 weeks) for nit picking things, inconsistently each time.

I know the app store can be like this, but it's been enough to push me back to being an android developer.

I love my macbook, but i might try rocking a graphene os phone.