We also have Ward who's multidimensional enough to play basically everywhere along the DL. Ellis is ideal for GL & short yardage packages.
the problem is (as @Simba has mentioned in the past) that we have no backup nose tackle outside of ellis on the roster so if we dont keep ellis then who fills in that role if BWill goes down or is gassed? - madubuike can play some 0tech but he's not a nose and tbh he's best suited to 0tech as a pass rusher
washington did a bit of nose tackle in college but again that's not the position he's best suited for in the pros
the worry would be that if brandon went down during a game who would step in to take those snaps without us getting run into the weekend