I have used three of these keyboards so far. One had a defect (one of the F keys fell out), but this was replaced under warranty. With the others, only the rubber feet are worn out. Otherwise they still run perfectly after 3 years.

Keys 2,3 and C no longer worked for us, the keyboard was then replaced by Digitec.

We have 3 K750s in use and the Ctrl keys have broken on two of them.

I have 3 of them and never a problem!

Yes, unfortunately I have noticed the same behaviour with the left Ctrl key on my K750. It bothers me because I often use the key combinations Ctrl-C and Ctrl-V, or I have no success with them.