Not sure I understand the last half of your question: “vs getting someone to work remotely for you from outside.” But here’s my two cents as a U.S. citizen living in South America:
I personally haven’t found it difficult to find jobs with fully remote, US-based companies. Since you’re not from the US (/don’t have a work visa), instead of putting you on payroll, they’d just hire you as a contractor—which I imagine would be easier for them since they don’t have to pay for your health insurance, part of your taxes, etc.
But as Anton mentioned, the prob comes in with coordinating between time zones. Not sure where in the EU you are, but you may have to work odd hours (late afternoon - night) to sync with those on the EAST coast… West coast is 3 hours behind them.
But if the fully remote, US-based company is also async, then this wouldn’t be too big of an issue for you… which you’re already experiencing.