As per a reliable source with clear accuracy on Rockstar plans, remasters of GTA IV & RDR1 were on the table a few years ago, but Rockstar chose not to proceed with the projects in mind.
Both Red Dead Redemption and Grand Theft Auto 4 remasters were “on the table a few years ago, but Rockstar chose not to proceed with the projects in mind.”
However, according to Kotaku, these projects weren’t fully canceled and could possibly see a return to development after GTA 6 releases.
The studio is now focusing on GTA 6, which was confirmed to be in development earlier this year.