The latest and official ROS2 paper came out on 11 May by the usual suspects below. It reiterates the already documented architecture, but also adds some new case studies. This is also on my reading list!
STEVEN MACENSKI, TULLY FOOTE , BRIAN GERKEY, CHRIS LALANCETTE, AND WILLIAM WOODALL
If you go through one of the links below you should have free access to it as granted for ROS fans. If you just google it, you may encounter a firewall.
Robot Operating System 2: Design, architecture, and uses in the wild (science.org)
DOI 10.1126/scirobotics.abm6074.
https://www.openrobotics.org/blog/2022/5/12/science-robotics-paper (takes two clicks to get to paper)
Jim