'Failed to Launch Game: An Error on Our End' for Multiple Games. Any Fixes?

So, now that this website is up again I can finally open this discussion...

I'm 26 hours into the game, haven't had any issues so far but yesterday as I was launching the game from Steam, I got "An error on our end caused the launch to fail. Try again a little later."
When I launch in Steam, it starts EA App, displays the Loading game progress bar which then disappears. For a short moment, EA App opens up again and shorty displays the error message then disappears again, and the Steam button goes back to "Play". Only when I start the game from the EA App do I have time to read the error message.

What I've tried :

• Repairing game files in Steam
• Clearing the cache of EA App, with or without admin rights
• Repairing EA App, which first resulted in getting stuck at "Connecting to EA" after relaunching
• Removing EA App with and without Revo Uninstaller and reinstalling
• Uninstalling the game and EA App and rebooting, then reinstalling everything (150GB yay)
• Disabling Steam and/or EA App overlays
• Going offline mode in EA App
• Launching directly from JediSurvivor.exe
• Sleeping over it and trying again the next day (here I am). Strangely, the app wouldn't launch anymore because it couldn't find the files (it tells me the app is installed but it's actually gone), so I had to reinstall it.

What else can I do ?