The xAI team says it will work closely with Twitter and Tesla.
Elon Musk has launched a new AI company called xAI with the goal of understanding the true nature of the universe. The team at xAI includes AI researchers who have worked at companies like OpenAI, Google, Microsoft and DeepMind. Little is known about xAI currently except that Musk seeks funding from SpaceX and Tesla to start it. The xAI team plans to host a Twitter Spaces discussion on July 14th to introduce themselves. xAI is separate from Musk's X Corp but will work closely with his other companies like Tesla and Twitter.
Your second question answers your first. The more he leaves Tesla alone, the better for them. It's probably pretty hard to determine how much having his name associated with Tesla is hurting the company vs how much it would help/hurt to get rid of him, but if he's attached but absent, it's very much a "devil you know" situation.