I'm having the same issue. Xcode 12.5, trying to install & build 'HelloKitura" as per the Kitura-next instructions, but for macOS 11.3.1. Xcode says "No such module 'Kitura' in main.swift. Similar problem with command line "swift build'...
warning: dependency 'Kitura' is not used by any target
[1/1] Planning build
/Users/mike/HelloKitura/.build/x86_64-apple-macosx/debug/Kitura.build/module.modulemap:2:12: error: header '/Users/mike/HelloKitura/.build/x86_64-apple-macosx/debug/Kitura.build/Kitura-Swift.h' not found
/Users/mike/HelloKitura/Sources/HelloKitura/main.swift:1:8: error: could not build Objective-C module 'Kitura'
After weeks of going round in circles, trying to learn just enough to get started, I'm seriously thinking of going back to Python. Please save me!