Looking at how often other projects are delayed, I doubt we will see DXB operations to be replaced before 2035 and then likely in phases. At first step I would see the non EK group airlines currently operated out of T1 to be transfered to their dedicated Terminal space and only later; weeks, months or even 1-2 years after the EK group which will be a big challenge but likely can be done over 1-2 days. Likely most operation can be transfered over in one go having all arrivals / departures after the night / morning wave land and depart at the new airport etc.