There is a lot of German ancestry throughout the country for sure. There’s a section of Philadelphia called Germantown because of the significant number of German immigrants that settled there. There’s also the Amish and Mennonites you may have heard of that are prevalent in PA and Ohio. The Midwest US’ culture of beer brewing was largely a product of all the German immigration. I think nearly half of people in Wisconsin have German ancestry if I recall correctly. What’s crazy too is, in the 20th century there were American towns that spoke German as the primary language. WWI mostly put an end to that though because there was a good amount of xenophobia that came out of the war.
As for American interest in their German ancestry, it definitely exists. There’s a German American club near my hometown. There are Oktoberfests regularly held throughout the country as well. My neighbors wear lederhosen for it, even. I assume our celebrations are poor facsimiles of what goes down in Bavaria, but it’s still a blast to drink beer and eat German food in the fall regardless. Americans overall like to look into their family heritage and there’s definitely a good amount of pride around it for most.
One final thing I will say about the German immigrants is, they were overwhelmingly slavery abolitionists and really helped drag the country out of the shameful institution. German and Irish immigrants made up a huge part of the Union Army. Immigrants are a good thing; people would really benefit to learn that.