Has is involvement with spacex ever helped tesla in anything (materials engineering etc)? My guess is yes.
Has his involvement in Tesla helped SpaceX with anything (thing electric motors for thruster gimbling) My guess is yes.
In terms of AI, has his involvement with things like OpenAI and xAI helped Tesla in any way? My guess is at least with respect to AI - yes, Tesla is not behind in AI because of Elon - but if anything is overdoing it in AI because of him.
Is he able to attract reasonable engineers to his companies despite sounding like an absolute pain to work for / with because of all of this? My guess is yes.