Did you install the steam-devices packages? That should do what you are trying to do.
Fedora Linux
All about Fedora Linux
Yeah, it's saying to just put the text "uinput" into that file.
It's basically just a list of kernel modules to load. You only need one kernel module, which's name happens to be "uinput".
What might confuse you, is that you already had to name that file "uinput.conf", but that name is actually completely irrelevant. It will just concatenate the contents of all the files in /etc/modules-load.d/, throw out the duplicate lines and then load all those kernel modules.
The advantage of a separate file like this, is that you can easily template it, if you want to script these setup steps, rather than having to build complex logic to try to check whether the "uinput" line is already in a given configuration file, and only adding it, if it isn't.
Here's some more documentation: https://www.man7.org/linux/man-pages/man5/modules-load.d.5.html
Standard worthless instructions for using FOSS due to assumed knowledge.
Sorry I can’t help with this one right now but I could maybe test it out later.