Hello,
I contacted the support, and after many steps, they asked me to follow these steps :
And guess what, it worked. And it led me to the reason why it wasn't working in the first place. On the new user account, my custom input method wasn't switched on.
I use an alternate keyboard and input method : Bépo, the French equivalent of the Dvorak. I just had to switch to Azerty or Qwerty on my main user account to make the game load perfectly.
It's strange because I never had any problems before on any game or app.
In any case, thank you for your help.