A 52-year-old man with newly diagnosed type 2 diabetes has an HbA1c of 66 mmol/mol (8.2%) despite 3 months of lifestyle intervention. BMI is 32 kg/m², eGFR 80 mL/min/1.73 m², and there is no clinical cardiovascular disease or albuminuria. What is the most appropriate next step in glycaemic management?