Sergey might have some positive influence on Gemini, but given that he isn't an AI scientist ( AKA no technical background), I really do wonder what sort of influence that (only) he could have had, beyond just bringing in key people.
The man that invented PageRank while going to college at Stanford for a PhD doesn't have a technical background? He did not get that PhD because he founded Google. He may not be as smart as you think you are, but he's no slouch either.
I assume by "no technical background" you mean he doesn't have a PHD in AI.
He's probably not developing the low-level algorithms but he can probably do everything else and has years of experience doing so.
He's also perfectly able to spend 60 hours a week improving his AI skills using the best teachers in the world.