Well, germanys economy is not solely reliant on exports to China, but they are significant nonetheless. Historically, we used to export a lot of cars to China, but ever since the EV boom german car manufacturers struggle because China heavily subsidizes its own car industry, making domestically produced cars much cheaper than the imported german ones. And technologically, China becomes ever more advanced so it increasingly doesn't need to import engineering equipment/machinery from germany as well.

But yeah, the decreasing exports are just one of many problems of germanys current economy.