Trying to write a Macro, but I cannot compile

Hello, I wanted to write my own Swift macro but I am stuck.

have installed the swift 5-9 dev toolchain. I verify it like this:

 % swift --version
Apple Swift version 5.9-dev (LLVM 299c632af12fe28, Swift f42cd3b53880c62)
Target: arm64-apple-macosx13.0

I created a new project as suggested here like this:

swift package init --type macro

This gave me this structure:

% tree                     
├── Package.swift
├── Sources
│   ├── terminal
│   │   └── terminal.swift
│   ├── terminalClient
│   │   └── main.swift
│   └── terminalMacros
│       └── terminalMacro.swift
└── Tests
    └── terminalTests
        └── terminalTests.swift

But when I run swift build I get:

 % swift build
Updated (0.55s)
Computing version for
error: Dependencies could not be resolved because no versions of 'swift-syntax' match the requirement 509.0.0..<510.0.0 and root depends on 'swift-syntax' 509.0.0..<510.0.0.

Sometimes I also get this (when VSCode detects a change):

Executing task: /Applications/ package resolve 

error: 'terminal': package 'terminal' is using Swift tools version 5.9.0 but the installed version is 5.8.1

 *  The terminal process "/Applications/ 'package', 'resolve'" terminated with exit code: 1. 
 *  Terminal will be reused by tasks, press any key to close it. 

It seems to use the wrong toolchain.. but how do I configure the right one? I thought swift --version is telling me it's correct?