HuggingFace LeRobot. You can build the reference arm easily and cheaply and the software is designed to train AI. There's a lot to explore and extend there and the community is growing rapidly. It's based on the Stanford Aloha project.
https://huggingface.co/lerobot
Probably not much.
Also the LeRobot reference arm (SO-ARM100) is 6DoF, but it's very hackable and there are already project with different grippers, etc.
