Welcome to Connect @chrisfeerer. I don't think doctors have forgotten about pseudoephedrine (Sudafed) but I'm not sure it's a first line treatment for COVID. I'm not a doctor but I've had Covid twice after having the 2 Pfizer vaccines and the first booster. If I had some around I may have tried it to help alleviate the congestion symptoms the first time I had Covid but I didn't and went to a Mayo Covid Clinic for an IV treatment. The second time I got Covid a little over a year after the first time, I had a milder case and really didn't have congestion just a lot of fatigue. Mayo Clinic has some information on how it helps here:

"A stuffy or congested nose may present with a cold, flu or COVID-19. Common decongestants include pseudoephedrine or phenylephrine, often labeled as "PE." These decongestants work by narrowing blood vessels, which temporarily relieves nasal congestion. However, they also can increase blood pressure in people with high blood pressure. Therefore, patients with hypertension, ischemic heart disease or kidney disease should use these medications with caution. When comparing these two medications, pseudoephedrine is more effective than phenylephrine. Pseudoephedrine does not require a prescription. However, it is placed behind the counter at pharmacies and requires a photo ID to purchase it."
-- Options for relieving cold, flu and COVID-19 symptoms: https://communityhealth.mayoclinic.org/featured-stories/cold-flu-covid-symptom-relief

Here are some references that may help explain a little better:
-- Pseudoephedrine and its derivatives antagonize wild and mutated severe acute respiratory syndrome-CoV-2 viruses through blocking virus invasion and antiinflammatory effect: https://pubmed.ncbi.nlm.nih.gov/34472141/
-- How do I treat a mild case of COVID-19 at home?: https://www.drugs.com/insights/treating-mild-cases-covid-19-home-3571321/