Does Xcode support anything akin to Visual Studio style #region directives for arbitrary code folding?
A useful option in XCode 12 (maybe before), is an option in preferences "Code Folding Ribbon"
When you check it, the source code looks like this
When you hover the mouse over this ribbon, you get foldable regions based on brackets, like this
When you click the Ribbon, it folds the bracket region, like this
Its not as the regions in Visual Studio, where you can place them wherever you want, but they're good enough to tidy up your code files.