Are there any pharmacological interventions that have been shown to reduce the effects of psychosocial stress at least in the short term?

This is one of the more disturbing things that will likely happen in the near term. The AI need not even be that good or visual for it to start affecting society. I think humans finding AI to be better conversationalists and empaths than potential friends or romantic partners will make people more bitter perpetuating a cycle of mistrust of other humans who will seem like assholes in comparison.

I hope we manage this as a society better than what we did with social media.

AGI is probably not needed for this. Understanding and manipulating biological systems is a pretty specific problem for which narrow AI can be made. It's mainly about having a good model (which we largely have now but AI models are not general enough to represent them well yet), generating a hypothesis to explain an observation / disease state (the main use of the AI), testing the hypothesis (the hard part currently) and then updating the model with the new information.

Of course, if completely new chemistry needs to be invented to solve some of these problems, then the AI needs to be more general. I don't think that's the case with something like biological ageing though.