If you role-play your character there is zero room for toying around with side missions once the story kicks in. cp77 simply isn't a do whatever you like game, it's a story game with a backdrop of a somewhat interactive surrounding. Compared to earlier cityscape story backdrops like e.g. in Deus Ex series games or the endless iterations of Assassins Creeds the backdrop is far more interactive and even a little gamified. But it shouldn't be considered the game, it's a backdrop.