I have a MX Keys and MX Master-3. I use Bluetooth only because 1of3 Easy-Switch PCs is secure and I can't add hardware. I'm using Windows 10 and my Logitec Options+ software is current. My firmware on my devices is current. I've searched you website and forum for my problem, and didn't find it. I have configured FLOW with [Hold CTRL...]
with my MX Keys Linked. The problem is the the keyboard often (but not always) does not follow. So, for example, after an initial single FLOW of the MX Master-3, I have to manually Easy-Switch my MX Keys. IN SHORT, THE KEYBOARD IS AUTOMATICALLY FOLLOWING ABOUT 1/2 THE TIME.