There is another quick way to do this from command line (Using x86_64 Rock system as an example):
Note (2025-05-18): These instructions are for dnf4 which is currently in use in ROME(rolling) and Rock. In Cooker we have now dnf5. These instructions may need to change for dnf5.
To enable main repository (should be already enabled by default):
$ sudo dnf config-manager --enable rock-x86_64 rock-updates-x86_64
To enable extra repository (extra repo includes community maintained and unmaintained packages, at lot work but some do not):
$ sudo dnf config-manager --enable rock-x86_64-extra rock-updates-x86_64-extra
To enable restricted repository (some packages in this repository may be illegal in some countries so be careful):
$ sudo dnf config-manager --enable rock-x86_64-restricted rock-updates-x86_64-restricted
To enable non-free repository (closed source code so we can’t fix anything inside these packages):
$ sudo dnf config-manager --enable rock-x86_64-non-free rock-updates-x86_64-non-free
If you wish to disable any repo substitute the option --disable for --enable. With the above example you should be able to extrapolate the commands to enable or disable anything you wish for any version. (Hint if you wish substitute either release, rolling, or cooker for rock.) (For different arch substitute znver1 for x86_64.)
And this is extremely, ultra, majorly, important. Do not mix the repository versions. If you use Rock use rock repos only. If you use ROME(rolling) use rolling repos only. If you use Cooker use cooker repos only.