Without seeing or knowing the specific details I can tell you that I have crummy sinuses that declared themselves on my first dive trip with reverse block and mildly bloody nose. Nasal steroids helped for years and then it got worse again with problems clearing the sinuses (not the ears). I did several years where I'd have a course of antibiotics+high dose oral prednisone until finally I lost my sense of smell and taste.....completely.
Got sinus surgery. Helped a LOT with diving, not at all with the sense of smell.
Had a lot of tests, tried a lot of things but nothing helped so I gave up on smelling and tasting for 7 years. Over that time I had to be very careful and easy with descents to not harm the sinuses. Even so, it got steadily worse.
Got a different ENT, did a lot of research and talking, and went for the 2nd sinus surgery. I actually had to talk him into it since he was open that he couldn't guarantee my sense of smell return. I knew that, but didn't have it anyway and no real hope of getting it back by doing nothing.
That surgery worked, diving/descent is easier, and I have about 50% sense of smell and taste back. I'm still on high doses of nasal steroids and regular sinus rinses, and some other more 'interesting' treatments but it's held out for a year.
So, I'd say barring specific problems or counterindications otherwise you have a good shot at improvement if you have a good surgical technician.