https://wccftech.com/grand-theft-auto-the-trilogy-the-definitive-edition-is-already-being-fixed-by-modders/

Grand Theft Auto: The Trilogy - The Definitive Edition has had a huge number of issues since its recent launch, from the Rockstar Games Launcher outage on PC to the underwhelming performance on both PC and next-generation consoles.

Luckily, the PC community has already begun fixing stuff. Performance can be improved by enabling DirectX 12 as a launch argument, for example.