Just discovered Synctrain (https://github.com/pixelspark/sushitrain) today. I don’t have Syncthing running yet, so no experience with this app. But maybe it‘s something for you to test if you feel limited with Möbius.

Had the same thought. Being able to run the robot offline with HA would be huge, and far better than getting one of the Chinese robots and flashing valetudo on it.