There are very few like for like Eriksen replacements out there though, especially if Brandt does go to Dortmund.
I think we'd probably (if Brandt goes elsewhere) be better off buying another quality 8, and a really top quality AM with some brains and composure who will pick up some of the creative/assists/goal slack that we will lose with Eriksen. Personally if we can't get Brandt, and we get NDombele, I'd think about Fekir and someone like Rabiot, Havertz, Aouar, Maxi Lopez, Tielemans and just playing a bit differently (433 more often hopefully).