Gazebo Garden installation problems with cmake and msbuild (Windows 10) - cmake

Question

I'm installing Gazebo Garden on my Windows 10 laptop and recently had some problems regarding building the ignition libraries with cmake.
First, I had an error that make couldn't run the msbuild command. The solution to that was to add the msbuild path to the system environment variables and to delete the cmake cache as in https://stackoverflow.com/questions/4... explained.
Here may be the first source of error. I changed the MS Visual studio version to the correct version of VS 19, but was not sure about the source and build folder. I set the source code folder to /ign-ws/src/ign-cmake from the installation manual (https://gazebosim.org/docs/garden/ins...) and the build folder to a new empty folder.
It kinda worked and I went on to build the libraries, but the command
colcon build --cmake-args -DBUILD_TESTING=OFF --merge-install --packages-up-to ignition-gazebo7
gave an error again. This time the error is something about the VCtargetsPath as shown in the error code:
(ign-ws) C:\Windows\System32> colcon build --cmake-args -DBUILD_TESTING=OFF --merge-install --packages-up-to ignition-gazebo7
Starting >>> ignition-cmake3
Starting >>> ignition-tools2
--- stderr: ignition-cmake3
CMake Error at CMakeLists.txt:6 (project):
Failed to run MSBuild command:
C:/Program Files (x86)/Microsoft Visual Studio/2019/Community/MSBuild/Current/Bin/MSBuild.exe
to get the value of VCTargetsPath:
Microsoft (R)-Build-Engine, Version 16.11.2+f32259642 für .NET Framework
Copyright (C) Microsoft Corporation. Alle Rechte vorbehalten.
MSBUILD : error MSB1009: Die Projektdatei ist nicht vorhanden.
Schalter: VCTargetsPath.vcxproj
Exit code: 1
---
Failed <<< ignition-cmake3 [1.41s, exited with code 1]
Aborted <<< ignition-tools2 [1.27s]
Summary: 0 packages finished [14.7s]
1 package failed: ignition-cmake3
1 package aborted: ignition-tools2
2 packages had stderr output: ignition-cmake3 ignition-tools2
13 packages not processed
I couldn't find any solution connecting both errors. Is the cause of my second error the false source folder? Maybe someone can help?