Xiaomi Mi Smart Air Purifier Pro - $299 (Normally $399) @ PC Byte
Can cover up to 60sqm area
Performance
500m³/hour CADR (Clean Air Delivery Rate) is higher than the international standard for measuring air purifier effectiveness. Rigorous tests are performed using dust, second-hand smoke and pollen to calculate the rate of clean air delivery per unit of time. The higher the CADR, the more effective the purifier.
35m²-60m² Recommended effective area: Effective area is based on the CADR and may be affected by factors such as room height and plot ratio.
Comparisons: https://www.mi-store.com.au/which-xiaomi-air-purifier-is-bes…
This is their largest purifier and can do bigger areas. Note - this one doesn't come with a HEPA filter but you can add one.