But can I develop iOS apps with vim? As in, easy to execute commands for debugging, running app and tests?
Yes, provided you are running vim on macOS, and calling into the xcode command line tooling.
Yes, But an iOS app requires a helluva lot more than just the Swift language. For example, Metal has zero support so you have to use ft=cpp and disable lsp diagnostics. And you can completely forget Xcode’s wonderful Metal debugger entirely.
Otherwise swift works just like any other clang/llvm project and the tooling is basically the same.
If you’re willing to try Neovim I’ve been using xcodebuild.nvim for a couple of years (for macOS not iOS, but they’re both supported).
https://github.com/wojciech-kulik/xcodebuild.nvim