US is one of the only countries in the world where you still have to pay US taxes no matter where you live or work and what passports you have, as long as you are a US citizen, and you can't give up US citizenship, which is also a paid process, unless you've paid all taxes.
But you said you're European. Are you a US citizen?
You can renounce a citizenship. They added an exit-fee recently. Plus if you've been living in the US working for a US company you've been paying taxes, no?
Or else you're under the table and not paying taxes, in which case this is all moot.
The US extends its power over financial institutions whenever it wants, so anyone who leaves the US without renouncing and then can't renounce due to incompliance is likely to end up unbanked eventually.
Likely and eventually are doing a lot of work for the US over decades, the hypothetical person is already unable to open a brokerage account since mid last decade in many countries.
First world children accidentally having US citizenship from their parents youthful indiscretions aren't so happy this decade with their inability to use normal financial services in their own country.
There's the possibility that the US gets sidelined in global finance but otherwise there's no reason to assume it won't continue with its current momentum instead of recently developed progressions somehow being steady state.
Going to the US as some kind of fun few year adventure is really no longer something someone should contemplate without first consulting non existent neutral international financial/immigration/legal council. If you aren't sure of a very specific goal/desire consider if somewhere else might work well enough instead.
