Dont know how long the virus takes to get from your nose/sinus' to your lungs but washing them out cant hurt.
NETi Xlear actually. https://www.amazon.com/Xlear-Sinus-...d=1&keywords=neti+xlear&qid=1586347985&sr=8-5
Takes neti-potting to the next level. I use sea salt, 1/2tsp./fill warm water. they suggest distilled water but I use tap. It's not the most natural feeling thing one does to themselves but one gets used to it.. dont do it just before bed time or just before you go to the market.. nose runs for some time after flooding. It's cheap and available.
Prevention.
I use a neti.
I add the premixed salts, and also a tablespoon of Alkolal terpene solvent