A 62-year-old male smoker with COPD presents with a history of 3 moderate exacerbations in the past 12 months, one requiring hospitalization. His post-bronchodilator FEV1 is 45% predicted. Blood eosinophil count is 180 cells/μL. He is currently on tiotropium monotherapy. According to the GOLD 2024 classification shown in the diagram, the patient falls into the category marked **D** (Group E — high exacerbation risk). Which of the following is the most appropriate INITIAL pharmacological management for this patient?