I'm going to jump on SadPanda's comment to add a quote from a Steam forums user called fathomdragon, who gave some advice that got the game running for me on Debian after I'd switched from windowed borderless to full screen and broke my game.
Fathomdragon said: "Like the original poster, I experienced this same behavior. The game loaded and played flawlessly for over 100 minutes at my first launch (on release day). In that session, I had changed a setting in the user interface to use "full screen" instead of "borderless window" (which oddly had a 1px white border). The game ran in full screen mode without issue. The next time I tried to play, the anti-cheat window displayed and then closed, then a black screen displayed full screen, and then nothing. There was no FPS counter, I couldn't click or press any keys to get past any "hidden" dialog, the game had to be forced closed.
As OP mentioned, deleting the config file would require the game to create a new one. I found my config file at ~/.local/share/Steam/steamapps/compatdata/553850/pfx/drive_c/users/steamuser/AppData/Roaming/Arrowhead/Helldivers2/user_settings.config
After changing around the config file a few times and settings within the game, it appears to remove the "screen_resolution" section from the config file when setting full screen mode in the user interface. Setting the values "maximized_window = true" and "fullscreen = false" let the game load and I was able to play again."
Follow the file path to the user_setting.config file, make those two true/false edits, then launch the game again. Worked flawlessly for me. Hope that ends up helping you. And shoutout to fathomdragon on the Steam forums, whoever you are, for posting the fix.
I'm going to jump on SadPanda's comment to add a quote from a Steam forums user called fathomdragon, who gave some advice that got the game running for me on Debian after I'd switched from windowed borderless to full screen and broke my game.
Fathomdragon said: "Like the original poster, I experienced this same behavior. The game loaded and played flawlessly for over 100 minutes at my first launch (on release day). In that session, I had changed a setting in the user interface to use "full screen" instead of "borderless window" (which oddly had a 1px white border). The game ran in full screen mode without issue. The next time I tried to play, the anti-cheat window displayed and then closed, then a black screen displayed full screen, and then nothing. There was no FPS counter, I couldn't click or press any keys to get past any "hidden" dialog, the game had to be forced closed.
As OP mentioned, deleting the config file would require the game to create a new one. I found my config file at ~/.local/share/Steam/steamapps/compatdata/553850/pfx/drive_c/users/steamuser/AppData/Roaming/Arrowhead/Helldivers2/user_settings.config
After changing around the config file a few times and settings within the game, it appears to remove the "screen_resolution" section from the config file when setting full screen mode in the user interface. Setting the values "maximized_window = true" and "fullscreen = false" let the game load and I was able to play again."
Follow the file path to the user_setting.config file, make those two true/false edits, then launch the game again. Worked flawlessly for me. Hope that ends up helping you. And shoutout to fathomdragon on the Steam forums, whoever you are, for posting the fix.