USB-C to HDMI connection disconnects and reconnects every 15 seconds?

Hello, I ordered a USB-C to HDMI adapter from Amazon. Since I'm always worried that something might not work with such cheap products, I ordered the Anker 518 USB-C adapter (8K HDMI) for €40. Now my problem is: When I connect my Samsung Galaxy S23 Ultra to my Phillips 65OLED706/12 TV or my monitor an…