Fg02,
Take particular heed of havick's comments about the requirement for an FAA ATP to fly for any US Part 121 airline. Perhaps the even bigger obstacle would be having the legal ability to live/work in the USA. As far as I know, at the moment no US carrier is taking EU pilots on visas. Seems your best chance
under current circumstances lies outside the USA. Best of luck.
If you just want to review the details of US regionals, try this:
https://www.airlinepilotcentral.com/airlines/regional