OS Setup
Install ubuntu 22 server (arm64). This works the best with ROS.
OpenCV
Cross compile on separate machine and install. This tutorial actually worked.
ROS2
Follow the installation instructions for ROS2 Humble.
Install ros-humble-ros-base & ros-dev-tools
Always remember to source /opt/ros/humble/setup.bash
Mavros
Follow the apt commands in the official instructions.