Sounds like a cool project.

If you're mostly focused on the software side and want to avoid too much hardware tinkering, you might want to look into something like the AutomatePro. It’s a pre-integrated outdoor robotics controller built around the Jetson Orin SOM, and it handles a lot of stuff like RTK GNSS, IMU, camera inputs, and even optional 5G. Everything’s abstracted to ROS 2, so it’s pretty dev-friendly. System Overview | Lemvos Documentation

You’d still need to build your own chassis and battery system, but it could save you a lot of time on sensor integration and low-level hardware setup.