What macOS version are you running? What version of Windows is running in the VM?

Could you post a copy of the .vmx file for that VM? It's found in the VM's bundle (find the VM with Finder, right click on it, and select "Show Package Contents". The window that then appears contains the .vmx file for the VM along with the VM's virtual disks and other configuration files).

Has anything changed in that VM since the keyboard stopped working?

Does the VM's configuration still have a USB & Bluetooth device? The virtual keyboard for a Windows 11 VM is a virtual USB device, and removing the virtual USB controller will remove the keyboard.