I am sort of struggling with similar issues, Randomly the entire screen will go to a flat color on all my monitors, computer will freeze, requiring a hard reset,
So far I was able to recreate this crash countless times using the landscape editor or any level that has an open world landscape.
If I try to create a new landscape while in Lit mode, it will freeze the computer that needs a hard reset, but If I do all my landscape editor things in unlit mode without using any other functionality of the engine besides the landscape editor, it works fine, but if I even open the project settings while in landscape mode it will do the same.
Levels without landscape does not seem to cause this. Same on 5.2 and 5.3. So my guess is it has something to do with recent nvidia drivers. Because 5.2 landscape editor used to work fine before april.
If anyone has found any solution to this please do share.