A 67-year-old man with a 45 pack-year smoking history presents with exertional dyspnoea and chronic productive cough. Post-bronchodilator spirometry shows FEV1/FVC 0.60 with FEV1 60 percent predicted. He has one moderate exacerbation per year but no hospitalisations. According to the 2023 Canadian Thoracic Society COPD pharmacotherapy guideline, which is the most appropriate initial maintenance pharmacotherapy?