Ultra

Rockstar Games had already officially confirmed and stated that GTA and RDR are not the same universe because New York City, New York State, California, Los Angeles, San Francisco, Las Vegas, Hollywood, Florida, Miami, Nevada, and New Jersey do not exist in the GTA universe, there's only Liberty City, Liberty State, San Andreas, Los Santos, San Fierro, Las Ventures, Vinewood, Leonida, Vice City, and Alderney that exist in the GTA universe.

Liberty City is the full replacement of

NYC in the GTA universe.

Liberty State is the full replacement of NY State in the GTA universe.

San Andreas is the full replacement of California in the GTA universe.

Leonida is the full replacement of Florida in the GTA universe.

Vice City is the full replacement of Miami in the GTA universe.

Los Santos is the full replacement of Los Angeles in the GTA universe.

San Fierro is the full replacement of San Francisco in the GTA universe.

Las Ventures is the full replacement of Las Vegas in the GTA universe.

Vinewood is the full replacement of Hollywood in the GTA universe.

Alderney is the full replacement of New Jersey in the GTA universe.

All RDR references in the GTA games and GTA VI promos are considered to just be Easter eggs and nods, not shared connections to the RDR games because Rockstar Games had already officially confirmed that GTA and RDR are not connected in the same universe.