Unfortunately, when our levels are high (which is common when our bodies are stressed by illness), we experience insulin resistance. I find I need twice as much bolus to correct a high over 15 compared to what I need to correct a 10.
Depending upon which basal insulin you take, you may also benefit from increasing your basal. I increased mine 40% when I had Covid. However, very long acting basal such as Tresiba may take 4 days for an increase to take affect.
I took a two pronged attack. Increased basal and corrected with bolus. Remember, basal should keep your levels stable do you need to lower them with bolus.