Small Restaurants Exist in Ancient and Modern Times, I Stock up to Feed the Whole Capital

Introduction to the work: My parents left, leaving me with a shabby restaurant and a debt of five million. Fortunately, the door in the utility room leads to ancient times. Three yuan of white sugar is sold for twenty taels of silver, and two yuan of cold medicine is exchanged for century-old wild ginseng. Before the debt was repaid, the door opened to the apocalypse and the high-tech world... Help, how many worlds is this restaurant connected to? (Easy to · Become a master across time and space · Make money to pay off debts · Save the world by the way)