Logitech Craft issue on 2018 Mac Mini


I'm trying to use a Logitech Craft keyboard and an MX Ergo mouse on 2 Mac minis - a 2012 model and a 2018 model. The 2012 mac mini recognises both mouse and keyboard without issue. The 2018 model 'forgets' the keyboard after a restart necessitating the removal of the device from the bluetooth devices list and re-addition - after using my old Apple keyboard to log in.
I have tried removing all listed bluetooth devices and trashing the bluetooth prefs list and re-adding them. This hasn't helped. I'm using the latest version of Logitech Options.
No issues with the mouse - simply works.
What else could I try?