a little correction: its not VLC that misses the codec, but the distribution. most distros dont risk distributing hardware acceleration drivers for h264 and a few others because of patents

To be clear, flatpaks from flathub. Fedora has their own flatpak repository, and those are not the flatpaks you are looking for.

Be aware though, that flatpaks can fill up your drive very quickly. Using something like Warehouse and Flatsweep every now and then to clean things up can free up a shocking amount of space.