Some of the keys fell off the refurbished x1 carbon laptop that I bought and seem damaged so aren’t going back on. Were they less frequently used keys I would live with it but F5 and T are keys that I cannot live without.

Wasn’t able to find reasonably priced individual replacement keys but found a replacement keyboard..

.. I probably should have had a look at the replacement procedure before buying.. this is not going to be fun!

https://www.ifixit.com/Guide/Lenovo+ThinkPad+X1+Carbon+6th+Gen+Keyboard+Replacement/154084

72 screws holding the keyboard in place.. and a whole disassembly adventure before getting to that stage. I am suddenly cognisant of why I stuck to desktop assemblies in the past.