Hello. It's constantly happening to me too. I'm working on important projects and it just suddenly restarts.
I isolated and disabled any T2 activity (at first I noticed it was very related to any of those processes starting with any security task) and for awhile everything went better (I disabled secure boot, touchid etc..). Beside the T2, from my experience there are some elements that trigger the restarts/freezes:
1) Sleep and wakeup
2) External hardware (monitor and hard drives)
3) Sound hardware/software related operations (in some cases just when I was simply running a audio software when I was setting the hardware preferences it crashed several times in a row, then I disconnected the thunderbolt 3 drives and it didn't crash anymore.. for now)
Just want to say that the Mac is perfect and surely there are no software conflicts. I had these problems right out of the box. I made a clean OS install, and all the softwares and such that I installed were perfectly working the day before on my previous iMac 5k. It took me almost 2 days to stabilise the MBP16 and still it restarts randomly (for the happiness of my 18TB external drives).
All the external hardware is from the latest generation with thunderbolt 3.
I use this Mac to work (I've spent almost 7000euros to buy it) and I can't just go to the Apple Store ad wait for their timing to fix it unless they won't change it with a new one with the same configuration right there (and replacing the internal SSD with the actual one).
I'm very disappointed because this Mac is the latest and the most advanced.. yet we have problems that really recall the amazing period of windows PCs in the 2000s.
Plus, Apple assistance is so focused on their rules that it become very hard to have a real support. Once again. I'm very disappointed. I really hope that someone at Apple will read our comments and contact us one by one to give us the support we deserve since we have built out workflow on their promises and products. It's really becoming too common that when you buy a software or a hardware, as user, you have to face problems instead of working with them!