“Can the flu be treated with just tylenol?”

Yes many people survive flu symptoms without the addition of an antiviral medication or else the flu in general would be much more deadly so as long as your condition improves and you’re not having any trouble with breathing or a huge amount of mucus burden Tylenol is fine with rest and time for recovery

Definitely. Most cases of influenza in young and healthy individuals don’t need antivirals. They can be treated like other common cold with fluids rest and pain/fever reducers as needed

Supportive therapy for symptoms of flu are mainstay in management. These include tylenol as needed for muscle aches and fever (temperature over 100.4F), hydration with fluids such as water, tea, soup (caffeinated drinks tend to dehydrate), lozenges for comfort and lubrication. However, the flu is a viral infection and as such tylenol is not a "treatment" for the flu virus itself.