Lenovo Ideapad Gaming 3 Laptop "no connected graphics card" Error

My Lenovo Ideapad Gaming 3 suddenly displayed a blue screen and then started reporting that it couldn't detect the graphics card. I called the authorized service center and explained the issue. I was told that formatting might resolve the problem, and we formatted the computer. After that, it seemed to be fixed. However, the next day, the same error reappeared: "no connected graphics card." The computer couldn't detect the graphics card, but it continued to work. I contacted the authorized service again, and they advised me to bring it in for service. Today, I brought it in for repair. I was told that they would provide me with a price quote, and if I agreed, after payment, they would proceed with the repair. Otherwise, I would have to pay 400 ₺. With no other choice, I agreed to the offer and left the computer. However, an hour later, I received a message with a price quote of 25,700 ₺. This seemed strange to me, so I called the authorized service to inquire about the high price. They explained that there is an issue with the motherboard, and it needs to be replaced. I checked the prices for a new laptop online and saw that it costs 19,000 ₺. However, the authorized service was demanding 25,700 ₺ just for replacing the motherboard, which I find peculiar. I expressed my dissatisfaction and stated that I do not agree with such an offer. Now I don't know what to do. I turned to the authorized service, considering it the most reliable place, but received such a strange proposal. If this is not unusual, then what is it? Please provide an explanation.