Do you have knowledge of actual need for any of what kernel-default-extra or kernel-default-optional provide? If you know you don't, they're just space wasters. Remove them, then lock them, to prevent future installation.
As I mentioned, later versions are already installed, as per yast software management. I never selected those extra packages, they were just part of the install.
If you know you do, or do not know, try from Konsole: zypper ref && zypper up
# zypper ref
&& zypper up
Repository 'Update repository of openSUSE Backports' is up to
date.
Repository 'Non-OSS Repository' is up to date.
Repository 'Open H.264 Codec (openSUSE Leap)' is up to date.
Repository 'Main Repository' is up to date.
Repository 'Update repository with updates from SUSE Linux
Enterprise 15' is up to date.
Repository 'Main Update Repository' is up to date.
Repository 'Update Repository (Non-Oss)' is up to date.
All repositories have been refreshed.
Loading repository data...
Reading installed packages...
The
following 3 package updates will NOT be installed:
kernel-default-6.4.0-150600.23.7.3
kernel-default-extra-6.4.0-150600.23.7.3
kernel-default-optional-6.4.0-150600.23.7.3
The
following 3 NEW packages are going to be installed:
kernel-default-6.4.0-150600.21.3
kernel-default-extra-6.4.0-150600.21.3
kernel-default-optional-6.4.0-150600.21.3
The
following 3 packages are going to be REMOVED:
kernel-default-6.4.0-150600.21.2
kernel-default-extra-6.4.0-150600.21.2
kernel-default-optional-6.4.0-150600.21.2
The
following package requires a system reboot:
kernel-default-6.4.0-150600.21.3
3 new packages
to install, 3 to remove.