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.
Go for it.
… and so forth. I don’t get paid to write this. 😄
More on this.