Thank you for this post i thought I was going crazy .. when I couldn't find anything on this !
Also having the Same issue since 10.15.2 ....
MacBook Pro (15-inch, 2017)
Intel Core i7 2.8 GHz
Memory: 16 GB
Radeon Pro 560
1TB SSD ony 50% full
Using a Thunderbolt Display but with or with out external monitor seems to crash at the same rate .
Not using any outrageous software . Mostly Apple - Safari Mail Music Notes doen't seem to be tied to any one
Really almost feels like a scheduled shutdown ? I looked for something in System Preferences but no joy ...
Odd is thing Mac never crashes or restarts when using the laptop .
Not getting the your Mac shut down due to an issue screen .
Walk Away come back & screen is Catalina Island with log in for User & Password
Doesn't matter what state I leave in sleep , hibernate with with out screen saver ...
Really Really getting tired of seeing Catalina Island !!!!!