There was an NFL development league in Europe for a while..’bout 25 years ago. It was part of an endeavour to form an International World football league I think they were trying to drum up interest in EUROPE. It did not materialize...so it was disbanded for Europe at least.
Teams were like the Rhein Fire, Berlin Thunder, Frankfort Galaxy, Scottish Claymores. Amsterdam Admirals. Barcelona Dragons, London Monarchs...
Amazing how much football occupies the minds and lives of American males. Couldn’t displace futbol(soccer) in Europe.
That was the old World League of American Football / NFL Europe. The two main problems were the level of play wasn’t very high and it lost a lot of money. Its demise (2007) corresponded with the NFL starting regular season games in London, which has been much more successful.