The Grub Boot Menu (list of operating systems) is not always so easy to obtain. When installing from flash drive, I found there were three entries in the BIOS related to my one flash drive. I had to choose the entry with ‘EFI’ or ‘Partition1’ to finally obtain a Boot Menu from installation.
Later, Fedora updates itself and so another entry goes into the boot menu. The old entry will probably never be used again, so how you do you remove an old entry (reduce clutter) ? Some take this to be a system complex with involved commands to reconfigure Grub (usually involving the grub.cfg file). But you may not even find a grub.cfg file this time (or grub2.cfg for that matter).
After looking around a bit, it simplifies by going to the directory /boot/loader/entries (root user) and moving the unwanted entry file to some other folder, such as your Home folder. It will no longer show in the Grub Boot Menu. You don’t have to remove the old kernel, which is best in case it is ever needed; you simply move the file back to /boot/loader/entries. Simple.
This “Grub business” seems to change with every version of Fedora. Not so simple.
Quick answer: change installonly_limit = 3 to installonly_limit = 2 in /etc/dnf/dnf.conf
By default, Fedora Linux systems keep 3 kernel versions when updating, including the currently-running one. That way after updating you’ll always have something safe to boot into. So, there won’t be infinitely-accumulating clutter in the menu.
If you prefer to have fewer (or more!) kernel options, check man dnf.conf and search for “kernel” to see the relevant options.The main thing you want to change is installonly_limit = 3 in /etc/dnf/dnf.conf. If you make this only 1, you won’t get duplicate kernel entries, but you may find that you need to boot from rescue media in the event of a problem with kernel update. This should be rare, but does happen (see https://discussion.fedoraproject.org/t/cant-start-after-update/72618/ for a situation some people are encountering now.)