The last 4.19 did not work, and I'm now waiting for 5.0 where the vega drivers are supposed to work. However, my trusty Debian Buster usb key could not install again, since my 4.17 no longer worked either. This machine has become so flaky that I've stored everything on other disks, and on the cloud.
I'm now doing everything on an old Chromebox. It does everything I need right now. I'll wait for the 5.0 kernel. I also have my stable machine for file storage.
News Flash - OMG, I changed a lot of things and now it works with 4.18 and Debian Testing. So many things! Now I have to wait to see if it freezes.
changes - bios, installed with Debian installer, current, graphical expert install, then changed to 'testing', installed some amd things on 'apt-cache search amd'. All working.