I would love to be able to see what keyboard shortcuts actually do, rather than just the key commands. For example, I use the buttons beneath the horizontal scroll wheel for copy and paste (I know you included those options, but I use them the opposite way your presets do. So for example, when I press the button and a dialog box comes out, it shouldn't just say "press key combination to assign shortcut," there should also be a box below that which says "Name shortcut reminder" or something like that. This would lead to something else I would REALLY like to see.
I like the edit pages and I think they do a pretty good job. But say I don't want to change anything, I simply want to be reminded what a button does, or what key command it represents. It would be great if I could press a button that would show a reference page that shows all the buttons and what they do, but that is separate from the edit page. That would accomplish a couple of things. First, if somebody else was using your computer, they could be reminded of what all the buttons do, without being able to mess with them. Also, I'm sure the page could appear more quickly, and be organized more aesthetically. That actually reminds me of another suggestion.
Again, let's say somebody else is using my computer and working on my project one day. What if they have their own MX Master 3. Perhaps their presets are totally different from mine. They would have to change everything around to suit their preferences, and then at the end of the day change them all back. Why don't you set up Logi Options just like the iMac. Give each person their own username and password. Then when our imaginary second employee sit down at my computer he can log into his own iteration of Logi Options (without having to give him his own Log-In and Password on my computer. Then if he's familiar with the Logitech mouse, he can make changes to his very own prefs, and they'll be here the next time he uses this iMac. And if he isn't accustomed to Logitech devices, he can open up the reference page and see what each button does, without having to worry about messing everything up. I used to work at a recording studio in Toronto. 90 percent of the time I worked in Studio 2. Whenever I spent a day in Studio 1, I had to change the trackball to reflect my prefs. But at the end of the day I had to remember to put them all back, so I didn't get a lecture from the Studio 1 engineer the next day.