https://www.youtube.com/watch?v=uCR_CdNCVlQ

cp /boot/grub/grub.cfg /boot/grub/grub.cfg.bak
cp /boot/initrd.gz /boot/initrd.gz.bak

// First list packages to delete //
ls /var/log/packages/kernel-*-5.15.193*

// Then run removepkg command //
removepkg /var/log/packages/kernel-huge-5.15.193-x86_64-1
removepkg /var/log/packages/kernel-generic-5.15.193-x86_64-1
removepkg /var/log/packages/kernel-modules-5.15.193-x86_64-1
removepkg /var/log/packages/kernel-source-5.15.193-noarch-1

Do not remove kernel headers because if we'll remove kernel-headers by removepkg command we delete key system directories f.e. for script compiling so system would start but we wouldn't be able to compile any package, even simple console program

Then check does removepkg command cleaned all old kernel symlinks and folders. If not delete them manually:

cd /boot
rm -f config-generic-5.15.193.x64 config-huge-5.15.193.x64
rm -f System.map-generic-5.15.193 System.map-huge-5.15.193
rm -f vmlinuz-generic-5.15.193 vmlinuz-huge-5.15.193
rm -rf /usr/src/linux-5.15.193

cd /boot
ln -sf vmlinuz-6.18.8 vmlinuz
ln -sf System.map-6.18.8 System.map
ln -sf .config-6.18.8 config

grub-mkconfig -o /boot/grub/grub.cfg