Even 21-25 AHI seems way too high. Normal is 5 or less. Greater than 20 is still considered severe. Could this be a positional issue? On nights when I sleep on my back I’ll have high numbers (30-40 AHI). If I stay on my side with good mask fit I am always under 8 and usually under 5. If not positional, it almost has to be that you need more pressure.