I have this MX Keys keyboard few years. Backlight stopped working. Same time heard a loose screw jumping around inside. Maybe related problems. I opened it, and noticed few other screws were almost loose. I screwed all back in, but backlight still not working. Also fake advertising images. Not only letters had backlight as I hoped, but also around keys. On good side, I like keys.
The productivity-focused peripherals made by the reputable Swiss company can now be ordered as a discounted bundle, which contains the fairly new Logitech MX Master 3S wireless mouse as well as the Logitech MX Keys wireless keyboard.