F39+Nvidia shows a black log-in screen

Thank you for your concern, but I did not execute that command. I did however execute the recommended change from the second link (which is indeed the one you recommend), which was unsuccessful.

UPDATE: I think in my second link, I copied the wrong one. Doh. That’s what I get for looking at six related post simultaneouly. Anyhow, the link that doesn’t work is: