It's funny, here in Montana one of the breweries here's owner and head brewer is from Bavaria and was trained there. Yet, his "Oktoberfest" is totally out of style....as you can see, it's "dark brown".https://www.bayernbrewery.com/oktoberfest
Even so, as it is malty and roasty, it's still pretty tasty for whatever it is. He makes a hefe that is the best American version I have ever tasted.
One of these types of beers I really like is Full Sail's Session Fest Beer. As someone mentioned earlier, it's a fine like between Marzen/Oktoberfest/festbier/Czech amber.
I think Oktoberfest is one of the easiest styles to brew at home. I like mine to be 1.060 OG, 1/3 each of pils, vienna, and light munich, and hopped to around 30 IBUs with nothing but Continental noble hops. Probably not to style either, but it's to my taste.