More particularly: American dairies have to feed their cows subsidized corn (maize) or be uncompetitive, which makes the butter markedly lower quality. Some American dairies actually dye their butter yellow. (Note that "Amish Roll" butter is the same, just sold in a different shape.) Certain boutique dairies do pasture their cows, and charge a premium price, but supermarkets mostly don't stock that.
In Ireland, cows eat grass. The US also gets butter imported from Poland, which is probably OK too. Neither government massively subsidizes maize.
To get a tolerable price in the US for Irish butter, you have to buy it from Trader Joe's, which is sort of like Aldi's in Europe. (Complicated story there.) [Edit: Or Costco, looks like.] Likewise, Parmesan cheese from Parma, Italy.
For many decades, the US government was telling Americans that saturated fat, as in butter and lard, was bad for their health, causing circulatory system disease. This, it turns out, was never true, and has long been known within the US Food and Drug Administration to be untrue. The diseases were, it turns out, caused by trans fats and sugar, both of which have been massively promoted. Trans fats were mostly banned in 2017, although certain companies get waivers to continue poisoning people.
Tl;dr: eliminate unnecessary sugar, add butter and lard from Ireland or other non-US sources.