The once solved problem came back with anything newer than Crimson 16.9.1 / Vulkan RT 1.0.21:
Weird lines and squares in the DooM (2016) multiplayer, singleplayer works like charm. The flickering is only gone when you use SMAA, anything else but that will cause this screen flickering. Seems like all maps (vanilla and all DLCs) have non or minor flickering, exept one map: Helix. This map turns out to be extreme with the flickering. There are even specific spots in the map where only one specific flicker happends. Mostly, i get vertical yellow and white lines and there is an upper-level area with an "air pressure elevator" where i get small flickering squares. Everytime i pass this specific area, i get these spots, rest of the map i get the vertical lines.
There is also a steam community discussion about it: