Your point still stands, but US federal spending is more like $4-7 trillion depending on the year. I assume you went based on Google’s answer box, which somehow confuses total GDP with government spending.

Doesnt the EU pass unfunded liabilities back onto the member states?

Meaning the EU will pass a law or regulation or program that the member states then have to fund with domestic taxes?

Generally speaking for the federal government, if they want to pass a program or requirement the federal government must also pay for that, for example the federal government could not require the state governments to put in bike lane on all road with out giving the states the money to do it.

That is why the Federal government is so large..

Also defense spending, We actually honor our NATO treaty by spending no less than 3% of our GDP on national defense, something the EU nations never do

that's because agencies used to implement federal policy (e.g. the FDA) are attributed to the federal government budget,

whereas the EU member state equivalents that implement EU policy get attributed to national budgets

the EU doesn't fund enforcement of the GDPR, the national information commissioners do

not having to pay to implement its policies makes the EU look many, many times more efficient than it actually is