To get evidence for why kernel-desktop-6.14.0-3 is not booting: Boot in to this kernel, then when you boot in to kernel-desktop-6.13.7-1 open Konsole or other terminal and run:
journalctl -b -1 > journal-no-boot.txt
The -b -1 options show the journal of the previous boot attempt. Post the journal-no-boot.txt file here. The journal log will tell us any kernel errors produced.
You could also try booting in to regular Plasma6 desktop instead of using this, maybe some module is missing form kernel 6.14.0. If so would be good to find out now.
Edit: To my knowledge it is not common for these to be installed unless you need them I would remove them.
kernel-desktop-modules-hfs-6.13.7-1.x86_64
kernel-desktop-modules-hfs-6.14.0-3.x86_64
Handy hint before we get caught by the forum police, read this, don’t we to see anyone getting their knuckles knocked by jack booted forum mods.