Onenote synchs really fast (in our experience), and if it doesn't, I combine it with Google Hangout/Meet or Zoom, with students sharing their screens so I can quickly see, at all times, how each of them is getting on (see image below, but instead of "people's faces" on the video, each those thumbnails is a "students onenote working out" pad). Double clicking on one of their "shared screen" thumbnails in Google Hangout/meet or clicking through each Students assigned Tab=workspace directly in Onenote, allows me to watch, live, what they do and don't understand and quickly give feedback.



Set your class a task, and in Onenote (synched via microsoft365), watch, live, which ever student tab you choose to click on, as they solve each question. We have the luxury of having used Onenote in this way for the last 4 or 5 years with our Grade11+12/Year12+13 students. I love it, for the following reason.
> Spot quickly who is struggling
> Give timely, tailored to the individual feedback, before they spend 10minutes on an unproductive line of inquiry/working out.
> Share students work quickly and anyonymously - I take a screenshot of their working out, it's rare a student who can tell who produced what work just from looking at how they write numbers/algebra etc. 
> Organising Student notes & finding them quickly - no more "lost notes" (they're all in the cloud) or "I can't find it". It also allows a teacher to quickly share examples of "well organised sections and pages (titled, Hwk section, Revision, Formula book section etc.)" and poorly organised (few section titles, few page titles etc.etc!).
> Teachers notes shared immediately - most of the time, the synching is so good students can see my working out live on their screens as I am writing on the board (in Onenote).

I used it in class too, via a VPN (e.g. Senso, Impero), which show all students screens directly on my screen as thumbnails. I find monitoring the working out of the whole class, simultaneously without having to peer over each student's shoulder and try and read clearly their working out a huge leap forward (I also use cheap, white, wallpaper around the walls, erasable pens for writing on windows and a set of giant whiteboards, but in this online environment, that is no longer possible!).