I'm not familiar with Swift's libraries, but what's the point of making this two lines instead of one:

  let request = URLRequest(url: url)
  let (data, response) = try await URLSession.shared.data(for: request)

  // vs
  let (data, response) = try await URLSession.shared.data(from: url)

That aside, your Swift version is still about half the size of the Go version with similar levels of error handling.