Adobe After Effects 2020 Preview Pane not working at all

Hi there - I'm in need of some serious help, rather quickly.

I just upgraded to a new macpro 2019, along with AE 2020, and none of my previous After Effects projects, nor any new compositions I create, will show the preview pane. For new compositions it keeps the "New Composition" and "New Composition From Footage" buttons versus showing the actual current composition's preview. And for my previous projects it's just a bit empty dark grey void. (see attached screengrabs)

I can select layers, and even create new layers (i.e. using the text tool to add text in the center of where the preview pane would be), but they won't show up. 

I've looked into the forum, and on other sites, and some folks with a similar problem have remedied the issue by determining it was an audio hardware issue. So I changing the audio hardware settings to something other than my LG 5k Monitor (using a display port connection.) However that didn't work for me.  I've also read that purging all memory and disk caches helps some folks, but still no luck for me. 

Any help/suggestions would be awesome. I'm a bit hung out to dry with my current project until I can get it working again. 

I'm using AE 2020 version 17.0.2, on a MacPro 2019, 2.5Ghz 28 core xeon W, with 192gb RAM, AMD Radeon Pro Vega II 32GB and Catalina 10.15.3 - using two LG ultrawide monitors, one is 5k the other is 2k.