Oddly seems to be taking a little time to populate - you could possibly look for rogue shell extensions particularly anything a bit unusual.
Shellexview is the normal (free) tool to start with- check box enable, disable for handling slow context menus.
However I'm not sure that's the cause of the initial transparent display and the 'blink' before the 2nd version appears - that's unclear.
Do you see the same in other cases - e.g. when rt clicking different file types in file explorer?
Is the resource usage as shown by your task manager low?
As for general visibility- consider a darker more uniform wallpaper with less detail.