Yes, the Unifying Reciever runs under Raspian. However, a package called Solaar must be installed for this.
See
https://pwr-solaar.github.io/Solaar
The installation is done via APT (advanced packing tool) in the shell. I'm not sure if the package can also be installed via the GUI.
>> Before I could use my MX keys, I first had to un-pair them and then re-pair them with Solaar.