Nothing you’ve looked up or said has any relevancy to the actual weapon under discussion.
First of all the Zumwalt class AGS does not fire Excalibur rounds. It fires the LRLAP, which has a bursting charge of 11kg of PBX (25 lbs for people in Burma, Liberia and the USA who still use Imperial measurements).
Second of all LRLAP is an artillery weapon so is designed to not destroy a point target via explosive blast but to saturate an area with lethal splinters. The bursting charge is what is used to break up the shell body to create splinters and energize them to lethal speeds. The LRLAP warhead is designed to have a lethality equal to the 155mm M795 HE shell. M795 is a typical enhanced lethality 155mm shell with HHS body to create more and higher energy splinters.
The third thing to understand is that each Zumwalt destroyer carries up to 920 of these shells and can fire up to 20 rounds per minute (two guns). As an artillery weapon it can be used from putting one shell onto a mortar team (as in the video of the Excalibur) through to putting large frontages of shells (eg 8 at a time spaced out over a large area to provide lethal effect to anything in that area) sustained over time (up to 60 minutes of barrage) that will totally deny that area to the enemy. This is called suppression. It denies the enemy the ability to manoeuvre so your own forces can and is also pretty lethal to anything in that area.
Artillery can also be used in a huge number of different ways and if the AGS program gets the long range ballistic shell program refunded will have a range of different shells other than the LRLAP. Including carrier shells for SFMs and the like (like SADRAM).
Vidoe of shell capabilities:
Long Range Land Attack Projectile (LRLAP) - YouTube
Video of how it will be used:
Navy Advanced Gun System Scenario: Non-combatant Evacuation - YouTube