If anything, it will give you someone that you can curse out.
If your sinus problems are being made worse by infection, and if the hydrogen peroxide, baking soda and kosher salt can get to the infected area(s), and to all infected mucus and debris within the nasal areas, then after your sinuses get over the impact of the flooding, hopefully you will see some improvement.
A lot of ifs. Only about 50% of those who have tried the upside down sinus flooding have experienced improvements in their sinus misery.
Some who have tried the flooding have only had mild reactions to the peroxide, while others have really been irritated, especially women.