I used Sudafed for months one summer in 2015 when I was suffering severe nasal congestion (basically unable to breathe through my nose 95% of the time), and it had zero effect on my tinnitus.
I'd recommend steaming with decongestant oils, alongside, or in lieu of, Sudafed though (esp. if you have a bad reaction to it), as this is my favourite (and most effective, imo) method of decongestion (for both the ears and nose).
Welp i am never using Sudafed again, it gave me tachycardia, I should have known since I have high bp. Bleh. But good news is my sinuses are clear as ever
@Damocles what oils do u suggest? I just had my first bad reaction actually lol. Usually it just gives me anxiety. But not today I guess. So I'm gonna not use anymore and just stick to sinus rinse and Flonase
@Shelbylynn, I'll link you the conversation I had with @ZFire on this. Most of my suggestions for Nasal/Eustachian Tube decongestion are there, and the advice is pretty much identical in both cases.