On MX Master Keyboard Paired on MX Master Mouse, perhaps there can be an a toggle switch on the Logi App that If switched device on the keyboard, the mouse switches also tags along.

Example: I am on Device 1 - PC using a receiver, then I want to switch to Device 2 - Android Phone, I just press the Device 2 button on my keyboard, then the mouse also automatically jumps to the device 2 (works on android or for individual who does not want to use flow)