Hello,
a while ago I designed, manufactured and made available commercially a low-cost LiDAR robot kit for ROS2 beginners. This includes Nav2, SLAM, Gazebo and complete step-by-step from-scratch video instructions. Everything is open source.
I’d like to share that the kit’s software has been upgraded to ROS2 Jazzy.
This includes porting all Gazebo simulations 
This means, if you are building (or migrating) a differential LiDAR robot for Jazzy or later - you can copy my working Gazebo simulations.
Here are pointers to more information:
- Kit Online Store | Maker's Pet
- Release announcement Kaia.ai ROS2 Jazzy Released | Kaia.ai
- Complete step-by-step instructions (Iron, just use the Jazzy Docker image) https://www.youtube.com/watch?v=RCPUQmvS37Q&list=PLOSXKDW70aR8uA1IFahSKVuk5ODDfjTZV
