Good news is you’re not alone, looks like the default controls are messed up for everyone. The ProtonDB listing for the game only has 5 reports, but 3 of them mention the default keybindings being messed up.

The PC gaming wiki has instructions for fixing this problem on windows. I’m not exactly sure how to fix it on linux though, you could possibly use protontricks (installable from the discover store), select the game prefix for DMoMaM, run regedit to edit the registry, and then delete the layout from HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Keyboard Layouts. Otherwise, your best bet is probably just to manually change the keybinds back. Here’s what the default keybinds should be, and here’s the AZERTY layout for reference.