Hello @S_B1, sorry to read you’ve found the guides to set up ROS 2 with ArduPilot hard to follow. Some of the documentation is still directed more towards developers than users and resides in the code READMEs. Our GSoC student @pedro-fuoco has done a great job and much improved the documentation but we may have still missed some steps. We welcome contributions and PRs to help us improve the wiki. The guide for contributing is here: Wiki Editing Guide — Dev documentation.
I think we’ve discussed getting your environment working in the ros Discord thread. The issue with tests is most likely the missing dependency mentioned here: Discord
sudo apt install ros-humble-launch-pytest