A 25-year-old man presents with a 2-day history of wheeze and cough triggered by a viral upper respiratory infection. He has a history of intermittent asthma, currently using salbutamol inhaler as needed once or twice per week. He reports two previous exacerbations requiring oral steroids in the past year. According to the 2021 Canadian Thoracic Society asthma guideline, what is the most appropriate controller strategy?