Which real-life cities have inspired the major cities of GTA?

Rockstar Games knew they had an absolute goldmine on their hands with GTA 3 and its expansive open world.

Which GTA city do you think is the greatest of all time? : r/GTA

GTA 6 Map: Leaks, Potential Size, Location, and More Details

GTA 6 Map Leaks & Vice City Location: Where will GTA 6 be set

GTA 5: Los Santos

I'm hoping to see multiple larger cities. Gta 5 had Los Santos and a series of tiny towns spread across the map and I think it made those towns essentially useless.

GTA 6 Map Leaks & Vice City Location: Where will GTA 6 be set

GTA 6 Map Leonida Is Packed With References to Real-Life Events From Florida - IGN

GTA 5: 10 Locations In Real Life - Los Santos VS Los Angeles

GTA 5 Locations Based On Real-Life

GTA 4 map with very accurate real life locations : r/GTA

GTA 6 Release Date, Map, Missions, Characters & Other Leaks - GTA BOOM

Since a lot of games are based on real cities (GTA V: Los Angeles, etc.), do I have to create my game to be based on a real city? Is it okay

Map of GTA:San Andreas based off of its real life counterparts. : r/GTA