From Fedora Project Wiki
Raspberry Pi5
Inoffical procedure:
Go to the RPM Fusion link https://rpmfusion.org/Howto/RaspberryPi Find the Fedora 40 (or 39) download (you’ll need to pick between Workstation and Server, haven’t tested server though) Install it (my only SD card reader was on my Mac so I used Etcher) Put the SD card in your Pi 5, and voila!
source by @kilobyte: https://discussion.fedoraproject.org/t/i-got-fedora-40-working-on-my-raspberry-pi-5/120319/3