Prior to getting into tech, I had an internship at the NY State Psychiatric Institute (NYSPI) where I did work helping people developing assessment tools for schizophrenic prodromes (people before they develop schizophrenia), as they were working on a predictive assessment questionaire.
Basically they were looking for risk factors but also to predict who might actually develop the disease imminently among those at risk, because if you monitor folks at risk, folks who might have subclinical symptoms, and can know who is going to have a psychotic break, you can manage and control it and have much better outcomes.
The largest predictive factor of folks who were at increased risk of developing schizophrenia is if they have a family history of it as I recall. Stress, in a variety of forms, is also a big factor.
However the reason I write is because I remember that late fall and winter conception of the individual has been shown to create a small but statistically significant increase in the likelihood of developing the disease. It's unclear exactly why, but one theory is that increased risk of viral infection for the mother during certain stages of pregnancy may be a factor.
Teasing apart these sort of facotrs, even to the extent possible often requires complex multivariate analysis of general and clinical populations and either time based or retrospective analysis of risk factors. Even then the mechanisms are fairly opaque.
Covid infection may lead to increased understanding of psychotic and subpsychotic disorders, but it's more likely to simply complicate any analysis; just teasing apart the actual effects of the disease and the stress that results from the social changes necessary to contain it, in terms of development of mental illness, may not be fully possible.