Battle.net launcher suddenly does not launch wow anymore

All of a sudden my battle.net launcher does not start World of Warcraft Retail anymore. World of Warcraft: Classic launches as expected, but when I try to start World of Warcraft, the game simply is not started.

I have gone through every step of the World of Warcraft Doesn’t Launch help page in several combinations, including/extended to

  • uninstalling and reinstalling the game
  • uninstalling everything and removing any remaining game data and then reinstalling the game
  • (sic!) uninstalling the game, removing any remaining data, uninstalling battle.net launcher, removing any remaining data as well, rebooting my computer, reinstalling the battle.net launcher, reinstalling WoW

Nothing changed.
When I try to launch Retail via the PLAY button, Version 8.3.0.34220. View the Patch Notes. to the right of the button vanishes and the button changes to Launching... for about 5 seconds and then changes back to PLAY.
Just about a second after the button click Game is running. appears right where the version number previously was displayed, just about 5 seconds later the text changes back to the version number.
During the whole time, no process is noticeably spawned in the process manager.

No error messages, just nothing. WoW Classic still launches just as before, though.
I spent half a day trying to get the game to simply start again. Please help!

Update 2020-05-01 09:00 CET:
I just literally uninstalled anything connected to WoW/battle.net (TSM, WoW, WoW Classic & battle.net launcher) and deleted any remaining data, rebooted my PC, freshly installed battle.net and WoW without making any changes and still can not launch the game.

Can you please upload your system files to pastebin.com and reply with the links to the files using the preformatted text option to encapsulate the links.

Some more detailed system information would allow us to provide better troubleshooting for this issue.