TL;DR: Someone please tell me how to set up an MX Master (v1) to work with KM, without using up normal hotkeys. 
I've used my MX Master for years with Logi Options without issue but since upgrading to Monterey my mac won't stay asleep and there are a few too many forum posts dotted around that blame this on Logi Options for me to ignore it as a potential culprit.
I found this thread which describes using mouse buttons as USB device keys. Great, but what do I set my buttons to be for them to be recognised by KM?
Expand for all available click types
Wheel mode shift
Gesture button
Middle button
Advanced click
App Expose
Back
Brightness down
Brightness up
Change pointer speed
Click
Desktop (left)
Desktop (right)
Finder Search
Forward
Keystroke assignment
Launchpad
Look up
Mission Control
Modifiers
Mute Sound
Next
Open application
Open file
Open folder
Open web page
Play/Pause
Previous
Screen capture
Scroll left
Scroll right
Search
Show desktop
Smart zoom
Volume down
Volume up
Zoom using scroll wheel
None
Another option is to assign each button an F13-F20 keystroke. I don't have phsyical keys to set those, so I tried simulating them via KM, and Logi Options doesn't respond.