The US spends more per pupil than every other OECD country except for Luxembourg, and exceeds the average by over 50%. If US schools aren't funded well enough, essentially no one is.
Not accurate in the context you're saying it.
You're probably conflating US K-12 spending (low) with post-secondary spending (high)?
https://nces.ed.gov/programs/coe/indicator/cmd/education-exp...
https://educationdata.org/public-education-spending-statisti...
Your source there still puts US K-12 spending in the top-5 worldwide.
The allocation of said spending clearly isn't optimal, but there is plenty of money at a high-level