Unable to play H.265 Video

You need to add the rpmfusion repos. The quickest way to get multimedia working would be this one line:

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 multimedia --setop="install_weak_deps=False" --exclude=PackageKit-gstreamer-plugin && sudo dnf groupupdate sound-and-video

It looks like a lot, but it is essentially just adding extra repositories, then downloading the most commonly used multimedia codecs etc.

Another good thing to do is to add Flathub for even more software.