Flickering Planes/Surfaces
Saw these around, thought they might help. (if they don’t, search around, I remember reading a ton of threads with similarish issues fixed with similar solutions)
https://forum-en.gw2archive.eu/forum/support/tech/Artifacts-Loading-Screen-In-game/first#post1725705
Follow up and post if either of these worked for you.
Or you may need to make sure all windows updates are current and installed or uninstall then reinstall the latest vid card drivers.
Wonder if this would help.
https://forum-en.gw2archive.eu/forum/support/tech/Black-Screen-Issue-AMD-ATI