Anyone have any current recommendations for an open source (or one that works without internet) robot lawnmower?

I've got 1,300m3 of grass around my house and it's been a pain to cut with a push mower.

So far I've only seen:

• OpenMower
• RepalMaker

My issue with the openmower one is that I don't know how to solder and I'm too afraid I'll break some very expensive components, so it would be nice if I could buy something mostly pre-built.

As for repalmaker, I worry not having GPS won't work since my garden is quite large and a robot bouncing around randomly would probably never finish, I also have a separate front and back (there's a path between them) and I'd like the robot to finish one area then, go to the other area by itself.

Anyone seen any other options available?