Very interesting comments Faustine. I would conceptualize structural factors including structural racism as shaping the environmental experiences people encounter. I don't think we need to restrict "environment" to a very narrow, individual level experience, but we can think of multiple levels of environment in which the individual is embedded. Those environmental factors may directly influence people (persistent noise, witnessing violence, lead or toxic exposures) or shape more proximal experiences, e.g., residential segregation--->underfunded schools--> low quality teaching --> poor labor market outcomes --> poverty--> etc. ( I skipped a lot of arrows here).
One issue in GxE studies to date (that I see) is they mostly focus on very narrow definitions of the environment (sugar consumption...). I think that's often a mistake when we are interested in social aspects of the environment.
Maria