Possible solution to this problem is to remove any mods / reshade files from the GTA V folder itself.
i.e \SteamApps\common\Grand Theft Auto V\
That’s what it should look like.
For good meassure once you have removed all the files that are not supposed to be there, verify the game files through Steam to make sure you got clean files.
Another possible solution after you have done the above things is to make sure that you have proper values in your settings.xml file.
The file is located in Documents\Rockstar Games\GTA V\
In there look up <Windowed value="0"/> and <VSync value="1"/>
Those values should be <Windowed value="2"/> and <VSync value="0"/>
Let me know if this worked or not for you!