GTA Online is a huge, enormously buggy and slow mess that will generally struggle to run at 80 fps on a top-of-the-line 2020 system (think 10900K at over 5 GHz with a 3090) and will almost never cross the 120 fps threshold no matter how fast your system is and how low the settings are.
I’m really confused as to why games are determining anything whatsoever based on the refresh rate of the screen.
Skyrim has this same problem and not being able to play over 60fps is the reason I haven’t touched the game in years.
If you then try to run the simulation in parallel with the rendering (rather than between some frames) it is even more work, since inter-thread communication is hard.
This stuff might seem easy for very good programmers, however on a game you want to hire a wide range of programmer skill and "game-play programmers" tend to be weaker on the pure programming front (their skills lie elsewhere)