A 41-year-old male with schizophrenia and type 2 diabetes mellitus presents for a medication review. He has been experiencing persistent positive symptoms including auditory hallucinations and paranoid delusions despite adherence to haloperidol 10 mg daily for 8 months. His HbA1c is 8.2%, BMI is 32, fasting triglycerides are 210 mg/dL, and fasting glucose is 168 mg/dL. He has no history of tardive dyskinesia. His endocrinologist has expressed concern about metabolic worsening with psychotropic medications. The PMHNP plans to switch to a more effective antipsychotic. Which treatment plan is most appropriate?