In the US marriage is not a federal institutional but a state one. I don’t know other state rules, I would be surprised if any require names to change.

I know that in California, at least when I got married, both people are allowed (or just one person) to take the others name or some combination of both names.

I was curious at the time, but never checked, if the combination could literally just be any combination of the letters of both. My guess is it would be the county clerk you deal with who’d decide to accept it or not.