Why not just use xylometazoline (aka Otrivin) at least as a nasal (spray) decongestant — or isn't it available in the U.S?

Xylometazoline is very effective. Sure that doesn't solve the oral/body-wide absorption of a decongestant but it's a good start.

From my personal experience phenylephrine (as a nasal spray) does work but it's one step off being useless. I've occasionally had to use it as a fallback when I haven't been able to get xylometazoline (where I am xylometazoline is only available in pharmacies whereas phenylephrine is also available in supermarkets and elsewhere).

It's interesting to note that the bans and restrictions on pseudoephedrine have had large negative consequences. Not only have ordinary users missed out on a good decongestant but it seems drug cartels have largely overcome the shortage of pseudoephedrine by substituting the precursor phenylacetone (P2P). Not only that but they've even managed to separate the chiral components of the final drugs which makes them indistinguishable from medical pharmaceuticals.

Incidentally, I prefer not to use pseudoephedrine as a decongestant, whilst I receive no mental stimulation from it, it nevertheless has stimulating properties that make me feel queasy. It's why my first choice is xylometazoline. There's also the related decongestant oxymetazoline, which I've found effective but it's not as good as xylometazoline (for me at least) but it's still vastly superior to the near-useless phenylephrine.