This did it for me 
Got a new monitor and had the same issue (no problems on my old one lol)
- first I got tearing: fixed it with lowering the maximum FPS to 60
- second I got the flickering - tried all the stuff from above; what fixed it for me was changing from DirectX12 to DirectX11
Good luck guys
I was being driven nuts by this with ‘Sandy coloured’ Graphics in Tenaris Inn and Area 52 Inn (Carpet Candles & Beds) flickering…
Fixed by:
Within Game: Options / System / Graphics
Bottom Left: [Recommended] then [These Settings] (I did not want the sound changed etc)
For me after clicking [These Settings] the flickering stopped straight away.
I reset ‘Environment Detail’ & ‘Ground Clutter’ back to what I’m used to.
Note: Selecting
Options / System / Graphics
[Classic] and then [Apply]
brings back the flickering, I did not spend time narrowing it down further.
Hope this helps.