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So you still have some flickering, even on the Nvidia driver?
That's odd, from what you said earlier your game and monitor resolution are lining up, so it shouldn't happen.
Well, one last thing you can try I can think of in that case, and it's more of a workaround than a real solution but you can give it a go to see if that fixes it;
Go back in your Nvidia control panel, this time go into 'Display' then the tab 'Change Resolution' you should see a 'customize' button on the bottom, click that, and check the mark saying 'Enable Resolutions Not Exposed by the display'. 
Once that's done, press the 'create custom resolution' button right under, and input '2560' as horizontal pixels, then '1800' as vertical pixels.
After that press the 'Test' button, it'll ask you if you want to keep the changes, agree.
Don't set up the resolution you just created, instead go into 'Manage 3D settings' to the left, once you're there, look for an option in your global settings called 'DSR factor' (that stands for Dynamic Super Resolution) select it and pick the new custom resolution you just created, it should show to the right as '1.78x DL', select it, validate, then try launching the game again and see if the problem still persists.
What that's basically gonna do is run the game at a higher resolution than your screen allows, then downsample it, that might solve the problem temporarily.