Anecdotal, but acetaminophen has been my goto for fever reduction. I've never had a problem with it (and it's taken me from 103->98 fairly frequently).
And, unlike most NSAIDs, it's safe(ish) for younger kids.
That said, I've never really noticed the pain killing effects.
Here’s an NIH meta analysis: https://pubmed.ncbi.nlm.nih.gov/33786837/
There are lots of studies out there, throw whatever symptom + acetaminophen effectiveness into Google for more. Just make sure that is a study is making a big deal about stat sig to check the actual treatment effect.
That is what it is supposed to do.
Ibuprofen is in almost all ways a better drug overall for parents/home use, but because of some rare reaction to it, it's not suggested until 6 months, so most parents assume Tylenol is "safer" and never switch over.
The thing about the weak fever reducing is it’s useful for reducing the suffering from the fever itself, like letting your baby sleep. It’s surprisingly ineffective at reducing febrile seizures. I think it’s that it doesn’t have much against a fever that bad.
My understanding is that for chronic pain the evidence is sparse, but for postoperative pain it definitely works.
It’s one of the most popular medications in the world and its use isn’t especially supported by science. To the point of this thread, don’t mistake official policy for rational behavior.