Try this:

sudo dnf update
sudo dnf install https://mirrors.rpmfusion.org/free/fedora/rpmfusion-free-release-$(rpm -E %fedora).noarch.rpm https://mirrors.rpmfusion.org/nonfree/fedora/rpmfusion-nonfree-release-$(rpm -E %fedora).noarch.rpm
sudo dnf groupupdate core
sudo dnf swap ffmpeg-free ffmpeg --allowerasing
sudo dnf groupupdate multimedia --setop="install_weak_deps=False" --exclude=PackageKit-gstreamer-plugin
sudo dnf groupupdate sound-and-video

You should also add the hardware accelerated codecs, by following the appropriate section depending on your hardware:
https://rpmfusion.org/Howto/Multimedia?highlight=%28%5CbCategoryHowto%5Cb%29

Make sure to reboot.

If this still does not work, install Celluloid and enjoy the superiority of mpv.