Hey @allib, welcome to the Stretch community! So in ROS1 Melodic, the Gazebo simulation came with a MoveIt configuration that enabled simulated use of MoveIt1. We deprecated Melodic a while ago, but if motivated, you can install Ubuntu 18.04, set up Stretch ROS1 for Melodic, and use the simulator with MoveIt.
Recently (in Jan 2025), support for the last ROS1 distribution, Noetic, was deprecated. With ROS2, I’d point you to try out Samuel’s implementation of an Ignition simulation for Stretch. Gazebo Ignition has replaced the Gazebo classic simulator from ROS1.
Also, if you’re getting started on Stretch hardware, I recommend going through the Getting Started tutorials.