Why can't I play H.265 videos on Fedora 38 even though I have the codec installed

Oh the good old days of suffering from a distro based on the US that has to follow the stupid laws of software patents and problems coming from all that shit.

One of the top reasons to use Arch when I started because of the pragmatic approach of do not giving a fuck.

a distro based on the US that has to follow the stupid laws of software patents and problems coming from all that shit.

That's one reason why Flathub exists and definitively much easier than to migrate to Arch.
Where are they based?

You want gstreamer1-plugin-libav from rpmfusion.

already have it
Libav is wrapper for ffmpeg in gstreamer. You need h265 in ffmpeg now.
- ffmpeg has a native decoder, would be odd for them to not enable it.

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.

I was actually using Celluloid before but videos were not playing until I used the commands you gave. Gnome videos is now crashing but I don't care as much since Celluloid is now working
- Can you run GNOME Videos in the command line and copy/paste the error output when it crashes?
- I was actually using Celluloid
  
  Celluloid is an MPV client and installing GStreamer codecs, as you did initially, does nothing. I didn't recognize Celluloid on the screenshot, though.

Avoid distribution eccentricities by istalling VLC from Flathub.

True. They created x265 afaik. I literally only layer libavcodec-freeworld on Fedora Kinoite and thats all I need. VLC does everything. BUUUT the Flatpak is not official! And there is already VLC 4.0 out! So helping the Dev is always important, and Videolan would make it officially maintained like the snap, if the Flatpak devs approach them and explain everything etc.
- x264 too. And dav1d. Cool people.
Oh. I was reading OP's problem, and didn't understand. I've been on Fedora for a while and never experienced this, but VLC is one of the first programs I install on every new distro.
This is the right answer

Didn't some distro remove hardware transcoding support for some non-free codecs for AMD hardware? I remember being really pissed at Manjaro for that a while ago when I noticed Plex was devouring my CPU. Maybe something related to that if you got AMD and hardware acceleration is forced?

I ran into something like this the last time that I installed Fedora. They have (or used to have) a fairly hardcore stance about nonfree codecs, which includes anything licensed under MPEG LA.

The codec in your screenshot probably doesn't include support for H.265 playback - at the very least it isn't in the list of formats. Here's a guide that I googled for you: https://ostechnix.com/how-to-install-multimedia-codecs-in-fedora-linux/

i've actually already followed that exact guide and it still is not working
- Well, dang! I'm sorry to read that. Codecs are definitely a tricky issue for Fedora.

The Fedora documentation has the answer: Installing plugins for playing movies and music

Fedora (combined with RHEL) has great documentation, take an hour, read the docs and you'll have a great experience.

I'm not sure what player you are using and what decoder it uses, but I suggest checking if you have h265 support in ffmpeg. If you do, you can play with ffplay anyway :)

insteall it from dnf, not flatpak

I had this problem, but after not being able to resolve it I tried Bazzite and found the gaming experience was much better there anyway, so switched. This problem doesn't exist on that distro.

I just installed fedora a couple of days ago and this happens to me too...

I guess I'll try a different distro 🤷‍♂️ it was being a nice experience until I tried to play a video

See my comment for the solution.
Just install VLC dude
- I mean yes, it's a way to solve playing offline videos, but it doesn't seem to stop there. I found that codecs for playing videos on Firefox are also missing
  
  I could install Chrome as well or hack my way, but it makes me want to recommend the distro to beginners even less
just use vlc
I guess I'll try a different distro

LOL

Just use VLC, problem solved