A 48-year-old woman with CKD stage 4 (eGFR 22 mL/min/1.73m²) secondary to IgA nephropathy presents with serum potassium 5.8 mEq/L, serum bicarbonate 18 mEq/L, and blood pressure 156/94 mmHg. She is currently on lisinopril 10 mg daily and amlodipine 10 mg daily. Urinalysis shows 3+ proteinuria. Which of the following is the most appropriate management for her hyperkalemia in the context of CKD?