@gnandanpai - Welcome to Mayo Connect! This is a very good place to share information and get input from other members with similar problems.
After reading your synopsis I recommend that you do try the treatment recommended by the ENT- antibiotics and prednisone.
Sinusitis, especially chronic, can be difficult to pinpoint. The CT says “polyploid mucosal thickening”.
I have a lifelong history of sinus illness- since childhood. I have had 2 sinus surgeries. Findings at the first procedure was identical to your CT report.
The second surgery just involved some minor corrections.
If you don’t try it, you will never know if there was any change at all.
Will you consider it?