PCPartPicker part list / Price breakdown by merchant
Parts are really expensive there in germany, I'm surprised. Anyway, This is a decent build for The Wicther 3 but it's enough for rocket league, estimated fps in Rocket League is 100+ at max setting. I've chosen a B450 chipset motherboard for future upgrade. It has 120 GB SSD for your boot drive. Very decent 1080p TN monitor, I couldn't get you a 144hz monitor with this high price of hardware.