I am using the latest version of Zoom, and Ubuntu MATE 18.04 on a Thinkpad X240. There frequently is some relatively mild, but certainly annoying screen flickering in Zoom. I have only encountered this in Zoom, not in any other applications.
Easy. Select on mate tweak - windows - window manager. Can choose different gpu rendering compositors.
Other possibility is, for example, try zoom on chrome extension, not in zoom app. Browser rendering will determine if display is flickering or not.
Lucky