It might be a good idea to hold onto the upper coast until Turkey calms down and gives up on revanchism. Then it can be given back. Owning Cyprus might put Greece in a stronger position diplomatically but it could get nabbed by a Great Power like in OTL.
Your thread is similar to these. Only difference is you want Ionia to be included.
https://www.alternatehistory.com/fo...tween-greece-and-turkey.438893/#post-16651480
https://www.alternatehistory.com/fo...comprise-this-territory.438728/#post-16636197
Greece would have a larger economy because it would be a larger country. Constantinople would be the second largest city in Greece and could in time surpass Athens to become Greece's largest city. However, it is not possible the city in TTL could ever approach becoming the Mega City Istanbul because in OTL it would be cut off from the heartland of Turkish Anatolia. Culturally and politically TTL Greece would probably be very different because of the absence of the population transfers we saw in OTL. If there were population transfers they would be different because of the scale would be different as well as where the refuges would go, maybe to Thrace. A lot of Greek history after the 1920s in OTL was the drama involved between the native Greeks and the refuges but that is not my area of expertise.