About 18 months for me. I had a lot of saliva and mucous along with dry mouth. My Covid pulmologist recommended flonase and prescribed a recombinent inhaler. That helped with lung issues and smoothing out mucus and coughing.
The bigger issue I believe is being dehydrated. I just don’t drink enough water and always feel thirsty. Maybe it’s partially the meds. I’m a sucker for energy drinks to keep my energy levels up, but I’m really trying to get to more water and no soft drinks. If you have an Apple Watch, I found mine was a water reminder on it.