I’ve had this issue for a little bit and haven’t found a fix for it.
Ever since I bought myself an asus RTX 5070 my computer takes a good while to shut down (i believe close to 20 minutes on the dot). A friend told me this may likely be because of a program hanging at shutdown. When i launch through Windows 10 it shuts down right away, so it makes me think it’s something in Fedora itself.
I also went ahead and updated my bios to the most up to date version to hopefully try to fix this a bit ago.
Hopefully there’s some way this can be troubleshooted.
I think if you switch to one of the VTs with, e.g., Ctrl+Alt+F3 and then reboot with Ctrl+Alt+Del, you should be able to watch the shutdown/reboot messages. If a graphic pops up and conceals the messages, try pressing the Esc key to dismiss it.