How to see all teamviewer monitors without switching between them?

Yes, you can just pop-out each monitor onto a different tab and then you can right click on the tab and select "Move to new Window." Then you just drag it to the other monitor and you have both open at the same time.

In TeamViewer12, go to View drop-down menu and uncheck Show session in tabs checkbox (View Options group). Check Monitors as individual windows checkbox, then click on each monitor symbol right above it (Monitor group).