Listen. I solved it! I know why it could not work on linux (probably in your case too). Initially I thought that GDevelop version was too old, (as it wasn't updated), because on the web version the gamepads worked and on games online too. Long Story Short. No, Snap or Flatpak versions of GDev are sandboxed and due to the sandboxing they get limited access to peripherals, thus gamepad input cannot be accessed unless you elevate the apps access in some way(Although I did not test snap!). The solution in my case was pretty obvious. I use an Appimage, And it works like a f#(%!#@ charm. The same problem occurs with Godot engine. I also recommend using Appimage on Linux due to filesystem access. (I could not use external text editor, vim, micro etc) I am not mad at flatpak, it does what it supposed to, it makes your system safe, and apps are up to date, but Appimage is the way to go for Gdevelop and Godot especially if you are on debian family.