Does anyone know a gaming pc that is sufficient for the games: Fortnite, rocket league, gta and minecraft are and is also good for office?
Yes, if you state your budget.
without a budget I would recommend https://www.hardwaredealz.com/bester-gaming-pc-fuer-unter-800-euro-gamer-pc-bis-800-euro.
What is your budget, what resolution, what settings and what is your requirement in terms of FPS?
Is he good? How good is that?