Here is a commercial robotic lawn mower that can take on difficult terrains. The SDNATURE ZCG-P03 Robotic Lawn Mower has a mowing width of 107cm with adjustable cutting height of 5mm to 150mm. It is powered by a single-cylinder 4-stroke 25HP motor.
This mower has two types of blades. It can handle slopes up to 60 degrees. The bad news? Something like this doesn’t come cheap.