My doctor didn’t prescribe anything much different than what we read from others such as Gargling with salt water, saline nose spray or mist, and mucinex to thin the phlegm. He also prescribed pantoprazole as I have symptoms of Gerd. The acid from Gerd can be irritating to throat which seems to make my phlegm issue worse so it helps me. However I only notice it helping when I stop taking it. Then I recognize that my symptoms flare so I assume , yes, it was helping.
I have not tried the zinc throat spray but I’m going to order it from Amazon tomorrow. It sounds promising. Have you used it?