BootSelector is a tiny GUI utility for setting any grub menu entry as default.
It also allows you to reboot into any OS/kernel in your grub menu.
The initial version has been tested on the latest Ubuntu 24.10 and should work on other Debian-based distributions as well.
An RPM for fedora will be released soon after more testing is done.
Grub customizer can do much more and was made a lot time ago