Swapping B777-X orders for B787-9 was a good move. Narrow bodies would also be worth considering as they open up destinations which can't support the B777, and allow gradual increases in capacity and frequency on routes. FlyDubai isn't an equivalent product so the aircraft need to be EK operated.
I think one of the reasons for getting the Max at FZ, along with the lie flat seats in business etc, was to align the 2 products a lot better.
The Max grounding didnt help with that of course but with new IFE's supposedly coming to the fz fleet next year, I think more enhancements are on the way to make it more of a EK style product on FZ aircraft. (with some limitations of course due to the size of the 737)
FZ has 200+ max's on order still, I see zero chance of EK ordering any narrow bodies.
(also, FZ has already been opening destinations for EK and taking over lower demand/seasonal routes which werent viable for EK)