Everything I do for macOS/iOS is already without Xcode but it's a pain in the ass to keep up with changes, and there are things I haven't figured out yet (like AUv3).
I feel like this needs a big asterisk. Can you ship a a non-trivial iOS or Mac app that uses SwiftUI or other first-party APIs without Xcode? Is it practical? Those are real questions, some cursory searching did not turn up a concrete answer.
It is possible and practical in lots of cases. And it's necessary to use the CLI tools directly in some situations, such as when deploying from CI servers rather than building by hand.
Is it possible for 100% of situations? I don't know, because I haven't tried 100% of the situations. And in one case I haven't figured out yet (AUv3).
Everything I do for macOS/iOS is already without Xcode but it's a pain in the ass to keep up with changes, and there are things I haven't figured out yet (like AUv3).