The ardupilot_gazebo plugin has been updated for Gazebo Garden. Gazebo Garden has binaries for Ubuntu 22.04 and built-in plugins for buoyancy, hydrodynamics and thrusters. See the project here: GitHub - ArduPilot/ardupilot_gazebo: Plugins and models for vehicle simulation in Gazebo Sim with ArduPilot SITL controllers
I built a model for the BlueROV2 running in Gazebo Garden here: GitHub - clydemcqueen/bluerov2_ignition: BlueROV2 model for Gazebo Garden
Let me know if you run into bugs.
/Clyde