American beef is some of the best along with british beef but different flavors. The reason MCD tastes better in europe, which it does, is because mcd is usually the lowest form of food you can get there but in europe it's quite expensive compared to what you spend here.
This results in a cleaner mcdonald's with higher salaried workers who don't hate their job and throw you half assembled sandwhiches .
But it's not because of the beef. You want good beef go to peter lugers in NYC. So far no fancy european steakhouse has compared with all the sauces they try to add on their beef.
Maybe you could try some Florentine beef. I ate here a few years ago and it was a hell of an experience.
https://www.dariocecchini.com/en/