You know, this seems like a perfect example of what a "simple" approach to scaling is: realizing that CI is the most likely thing to cause issues in the future due to how popular it is and then splitting the database along that particular boundary, due to the actual need that has arisen.
You don't always need to experiment with bleeding edge tech or very complicated multi-leader clusters (though those also have their own use cases at a certain scale), sometimes just splitting the whole thing, especially when using something as solid as PostgreSQL, is enough!
You don't always need to experiment with bleeding edge tech or very complicated multi-leader clusters (though those also have their own use cases at a certain scale), sometimes just splitting the whole thing, especially when using something as solid as PostgreSQL, is enough!