This command you used was enough to install the rpmfusion repository on Fedora, this is just one step of the process on running Vulkan games on Nvidia in a Fedora installation.
Now I’m going to give you the command to install the Nvidia driver, but be careful, if you are on GNOME (Fedora Workstation), is desirable to go on the login manager and to click on the gear symbol to select a session of GNOME with Xorg before using the following commands:
sudo dnf install xorg-x11-drv-nvidia akmod-nvidia
sudo dnf install xorg-x11-drv-nvidia-cuda #optional for cuda/nvdec/nvenc support
sudo dnf update -y
I also recommend you install Steam, it’s a great gaming platform, and it will probably get some nice packages as dependencies for you, so go to a terminal, and type:
$ sudo dnf install Steam
Type your password on the terminal and Steam is all set.
After that, probably you already have Vulkan set with your Nvidia driver. But if you want to be sure you can run the following command:
$ sudo dnf info vulkan-loader
The vulkan-loader packages in 32 and 64 bits must be listed as installed.
Of course, for your purposes, i also recommend you to install Lutris:
$ sudo dnf install lutris
And Wine, for proper Lutris functioning:
$ sudo dnf install wine
Ps: if you have some doubts with the GNOME with Xorg process, point me out, and i will upload some pictures showing you the process.